Genuine-spec US layout (QWERTY) black keyboard replacement for MacBook Air 13.6″ and 15″ models (2023–2025, M2/M3/M4 chips)—featuring Apple’s Magic Keyboard with scissor-switch mechanism, backlighting, and precise OEM fit. Compatible With: 13.6″ MacBook Air: A2681 (M2, 2022–2023), A3113 (M3, 2023–2024), A3240 (M4, 2024–2025) 15″ MacBook Air: A2941 (M2, 2023), A3114 (M3, 2023–2024), A3241 (M4, 2024–2025) 13.6″ MacBook Air: A2681 (M2, 2022–2023), A3113 (M3, 2023–2024), A3240 (M4, 2024–2025) 15″ MacBook Air: A2941 (M2, 2023), A3114 (M3, 2023–2024), A3241 (M4, 2024–2025) Keyboard Layout: Standard US English (QWERTY) with wide Enter key, dedicated left/right arrow keys in inverted-T layout, and full function row—matches Apple’s original US configuration. Design: Apple’s Magic Keyboard with scissor-switch mechanism—providing quiet, stable, and responsive typing with 1mm key travel and enhanced durability. Features: Integrated backlighting for low-light use, ambient light sensor compatibility, and OEM-style flex cable for direct logic board connection. Color: Sleek black keycaps—ideal for Space Gray and Midnight finishes, and visually consistent across all color variants. Precision Fit: Engineered to exact Apple specifications for alignment, key spacing, and mounting—ensures seamless integration into the original top case. Installation Note: The keyboard is factory-glued into the top case. Replacement requires full disassembly, careful removal, and professional-grade re-adhesion. Recommended for experienced technicians only.
MARSRIVA Smart Mini DC UPS KP2 Series | 18 Watts 10000mAh | 0ms AC to DC Transfer | Flame Retardant | Wall Mount Slots | 1 x Passive PoE, 2 x DC and 1 x USB Output Ports | KP2 BLACK Keep Wi-Fi Power On Output:18W (Max.) or 30W (Max.) ● With 1 * Passive PoE, 2 * DC and 1 * USB output ports, DC UPS can power up multiple devices simultaneously. ● AC to DC 0ms transfer technology keeps your devices working when electricity is ON/OFF shifting. ● With wall-mount slots on the back, DC UPS can be mounted on the wall easily. ● Air cooling system provides maximum heat dissipation, ensuring the long-term stability of UPS. ● V-0 flame retardant product housing secures you and your property. ● 16000mAh high-capacity battery (KP2 Plus, KP2 Ultra) provides longer backup time. ● 30W high-power output (KP2 Pro, KP2 Ultra) provides better compatibility.
The ViewSonic VX3211-4K-mhd 32″ 4K Monitor is designed to transform your visual experience. Whether you’re working, gaming, or watching movies, this monitor delivers crystal-clear images with incredible detail. Featuring a stunning 32-inch 4K UHD display, the ViewSonic VX3211-4K-mhd provides four times the resolution of Full HD. This means you can enjoy sharper images, vibrant colors, and exceptional clarity, making every detail come to life. The ViewSonic VX3211-4K-mhd supports a wide color gamut, ensuring that colors are accurate and true to life. This makes it an excellent choice for graphic designers, photographers, and video editors who need precise color reproduction. With multiple connectivity options, including HDMI, DisplayPort, and Mini DisplayPort, the ViewSonic VX3211-4K-mhd offers versatility for connecting various devices. Whether you’re connecting a computer, gaming console, or other multimedia devices, this monitor has you covered. The ViewSonic VX3211-4K-mhd also features advanced eye care technology. Flicker-Free and Blue Light Filter functions help reduce eye strain during extended viewing sessions, making it comfortable for long hours of work or entertainment. This monitor is also designed with an ultra-slim bezel, offering a sleek and modern look that complements any workspace or gaming setup. Its VESA compatibility allows for easy mounting, giving you the flexibility to set it up the way you like. In conclusion, the ViewSonic VX3211-4K-mhd 32″ 4K Monitor offers stunning visuals, vibrant colors, and versatile connectivity. Upgrade your display today and experience the difference that 4K resolution can make. Specifications: Display : 32″ UHD Resolution : 4K (3840×2160) Refresh Rate : 60Hz Response Rate : 3ms
The Samsung 77 OLED S85F 4K Vision AI Smart TV QA77S85FAEXTW delivers a premium home cinema experience built on advanced OLED technology. It produces deep blacks, rich colors, and strong contrast, so movies, sports, and games look more realistic on the large 77-inch screen. OLED technology controls each pixel individually, so every detail appears with high precision. This improves dark scenes by keeping blacks deep and detailed, while bright areas stay clean and accurate. As a result, the picture stays balanced in both bright and dark environments. Samsung Vision AI improves picture and sound in real time. It analyzes each scene and adjusts brightness, color, and sharpness automatically. Therefore, the Samsung 77 OLED S85F 4K Vision AI Smart TV QA77S85FAEXTW always delivers optimized visuals without manual settings. In addition, AI upscaling improves lower-resolution content closer to 4K quality. HDR expands contrast and color depth, making visuals more lifelike. Fast motion also appears smoother and clearer, which improves sports and action viewing. The Smart TV system gives access to streaming apps, games, and smart home features. It runs smoothly and is easy to navigate. In addition, the slim design with thin bezels gives the Samsung 77 OLED S85F 4K Vision AI Smart TV QA77S85FAEXTW a modern, premium look. Overall, this Samsung OLED TV combines strong picture quality, AI optimization, and smart connectivity for a high-end viewing experience. Specifications: OLED technology delivers deep blacks and rich color accuracy 77-inch 4K display provides immersive large-screen viewing Vision AI optimizes picture and sound automatically in real time HDR enhances contrast, brightness, and color depth Smart TV platform supports streaming apps and smart features
Genuine-spec touchpad flex cable for MacBook Pro 16″ (Model A2485, 2021, M1 Pro/Max)—critical for restoring full Force Touch functionality, haptic feedback, and precise multi-touch gesture control during trackpad repairs. Compatible With: MacBook Pro 16-inch (2021, Model A2485) with Apple M1 Pro or M1 Max chip (Model Identifiers: MacBookPro18,1 / MacBookPro18,2). Part Type: Touchpad flex cable only—does not include the trackpad, Taptic Engine, or mounting hardware. This is the OEM-style ribbon cable that connects the trackpad to the logic board. Function: Transmits touch coordinates, Force Touch pressure data, and haptic feedback signals—essential for macOS gestures (e.g., pinch-to-zoom, Force Click, three-finger lookup) and Taptic Engine operation. OEM-Quality Construction: Precisely replicated to Apple’s original specifications—including cable length, connector type, EMI shielding, and flex routing—ensuring signal integrity and long-term reliability. Common Use Cases: Replacing a torn, frayed, or liquid-damaged original flex cable Completing a trackpad replacement when the original cable is compromised Fixing intermittent trackpad behavior, lost Force Touch, or complete unresponsiveness Replacing a torn, frayed, or liquid-damaged original flex cable Completing a trackpad replacement when the original cable is compromised Fixing intermittent trackpad behavior, lost Force Touch, or complete unresponsiveness Installation Note: Requires full disassembly of the bottom case and careful routing around the battery and logic board. Connectors use ZIF (Zero Insertion Force) sockets—must be aligned and latched gently. Recommended for certified or professional repair technicians only.
The Samsung ViewFinity S7 27″ 4K Monitor is an outstanding choice for anyone seeking a clear, high-resolution display. This 4K monitor offers crisp visuals and vibrant colors, enhancing your viewing experience for work, gaming, and entertainment. With a 27-inch display, this monitor provides a large screen space to increase productivity. The 4K UHD resolution (3840 x 2160) offers four times the clarity of Full HD, so every detail is sharp and vivid. Whether you’re editing photos, creating designs, or just enjoying high-definition content, this monitor brings every image to life. The Samsung ViewFinity S7 4K Monitor is designed with a slim, minimalist look. It features ultra-thin bezels, allowing for a near borderless viewing experience. This makes it ideal for dual-monitor setups, as you can position screens side by side seamlessly. Setting up the monitor is simple, with multiple connectivity options like HDMI and DisplayPort. It also features USB-C compatibility, allowing for fast data transfer and device charging, reducing the need for multiple cables on your desk. This Samsung 4K monitor supports HDR10, providing higher contrast and accurate colors for a richer picture. Its wide viewing angles ensure that the image stays consistent, even when viewed from the side. This is perfect for shared workspaces or group settings. Additionally, the Samsung ViewFinity S7 has advanced eye-care technology. It includes features like Eye Saver Mode and Flicker-Free technology to reduce eye strain during long sessions. Upgrade your workspace or gaming setup with the Samsung ViewFinity S7 Monitor and enjoy stunning visuals. Specifications: Display : 27″ VA Resolution : 4K (3840×2160) HDR10 Refresh Rate : 60Hz Response Rate : 5ms
Its 31.5″ Rapid VA panel features a 1500R curve for immersive visuals. Plus, Dual‑Mode lets you switch between 4K@160 Hz or FHD@320 Hz resolution easily. Also, the monitor offers a fast 0.5 ms GtG response time to reduce blurring. Because of AMD FreeSync Premium, gameplay stays tear‑free and smooth. Moreover, VESA DisplayHDR 400 enhances contrast and color accuracy. It covers 97 % DCI‑P3, 93 % Adobe RGB, and 136 % sRGB for vivid colors. With HDR and AI Vision tech, dark scene details become clear. Also, it supports HDMI CEC, PIP, and PBP for multi‑device setups. Furthermore, ports include DP 1.4a, two HDMI 2.1, and USB‑C with 15 W PD. Also, anti‑flicker and low‑blue‑light tech reduce eye strain over long sessions. Plus, the frameless design gives a sleek look to your setup. The ergonomic stand adjusts tilt and height up to 130 mm. Moreover, headphone‑out jack adds audio convenience. Because of dual‑mode, you choose either crisp 4K or ultra‑fast FHD. Gamers love the 320 Hz FHD mode for competitive play. Also, movie and design work shine in 4K HDR mode. Additionally, AI Dual‑Mode auto‑switches resolution and refresh rate. Furthermore, build quality feels solid with metal stand and VESA mount. Also, cable routing is tidy despite downward ports. Thus, the MSI MAG 321CUPDF suits high‑end gaming and creative workflows. Upgrade today to enjoy ultra‑fast refresh, vivid visuals, and smooth gameplay. Specifications: Display : 31.5″ Rapid VA Resolution : 3840 x 2160 (UHD) / 1920 x 1080 (FHD) Curvature : 1500R Refresh Rate : 160Hz / 320Hz Response Rate : 0.5ms (GTG)
BATTERY TOSHIBA PA5136U-1BRS for Toshiba Portege Z30 Z30-A Z30-A1301 Series PA5136U Tablet Rechargeable Notebook Battery Pack 14.8V 3380mAh About this item Battery type: Voltage: 14.8V Capacity: 3380 mAh(52Wh) Cells: 4-cell Li-Polymer 100% New from Manufacturer Full Compatible for Part# PA5136U-1BRS,500+ recharge cycles over Every battery has passed factory testing; CE-/FCC-/RoHS-Certified ensures safety. Grade A cells battery; Quality assurance This compatibility list is non-exhaustive, if your original part# or your laptop model NO is not included in the compatibility list, but our battery may still fit your laptop. Please feel free to contact us to confirm the compatibility
Non-slip, skid-proof rubber feet designed to perfectly fit MacBook Air models A1466, A1369, and A1370—restoring grip, stability, and protection for your laptop’s base. Keep your MacBook Air steady and scratch-free with these high-quality replacement rubber feet, engineered to match the original Apple design for MacBook Air models A1466 (2010–2017), A1369 (11″ 2010–2011), and A1370 (11″ 2011–2015). These skid-proof rubber feet provide excellent traction on desks, tables, and other smooth surfaces, preventing unwanted sliding during typing or use. Made from durable, soft-touch silicone-rubber material, they also help protect your laptop’s bottom case from scratches and reduce vibration noise. Each set includes all necessary feet (typically 5 per MacBook Air model) with pre-applied adhesive for easy, secure installation. The matte black finish blends seamlessly with your MacBook’s original aesthetic. Ideal for restoring worn, missing, or damaged feet—whether due to age, cleaning, or accidental removal—this is a simple, affordable way to maintain your MacBook’s functionality and appearance. Note: Surface must be clean and dry for optimal adhesion. For best results, gently warm the adhesive before applying.
The LG 27U511SA-W 27″ FHD IPS Smart Monitor with Speakers is built for comfortable viewing, entertainment, and everyday productivity. Its 27-inch Full HD IPS display delivers clear visuals and consistent colors, making it suitable for work, streaming, and browsing. Moreover, the IPS panel ensures wide viewing angles so images remain accurate from different positions. This smart monitor allows direct access to streaming apps without requiring a connected PC. Additionally, the built-in speakers provide convenient audio for movies, meetings, and casual gaming without external devices. The slim and modern design fits easily into home or office environments while keeping your workspace clean and organized. Connectivity options allow easy connection to laptops, consoles, and media devices. Furthermore, ergonomic adjustments help users maintain comfortable viewing positions during long sessions. Therefore, the monitor suits home users, students, and professionals seeking versatility and convenience. Finally, it combines smart functionality, quality visuals, and built-in sound for daily entertainment and productivity needs. Specifications: 27-inch Full HD IPS smart monitor Built-in speakers for convenient audio Smart features for direct streaming access Wide viewing angles with accurate colors Modern design with versatile connectivity
GSAN GS-3021 POS All in One Touch 15.6" - Intel i5 - 8GB - 128GB SSD with Customer Display Main Board: POS motherboard CPU: I5-3RD GEN Memory: DDR3 8GB Hard Disk: 128GB Power: External power supply Input: 110V-240V 50/63Hz 2A Output: 12V DC 8A 96W MAX Interface: 6 USB port 1 LAN port
MacBook Pro A2485 2021 – 16.2" XDR display, Apple M1 Pro (10-core CPU / 16-core GPU), 32 GB memory, 512 GB SSD.Top-tier creative laptop with blazing performance, superb display, and professional I/O – built for demanding workflows.
The ViewSonic 27″ 180Hz Gaming Monitor delivers an ultra-smooth gaming experience. With a 180Hz refresh rate, every motion looks fluid and lag-free. This makes it perfect for fast-paced games like shooters and racing titles. Featuring a 1ms response time, the monitor reduces motion blur and ghosting. You get sharper visuals and smoother gameplay, giving you a competitive edge. Say goodbye to input lag and enjoy instant reactions. The ViewSonic 27-inch Gaming Monitor offers Full HD resolution for crisp and detailed visuals. Whether you’re gaming, streaming, or working, you’ll enjoy clear images with vibrant colors. The IPS panel ensures wide viewing angles and accurate colors. With AMD FreeSync technology, screen tearing and stuttering are eliminated. The monitor syncs with your graphics card for seamless gameplay. This ensures a smoother and more immersive gaming experience, even in demanding scenes. This monitor is designed for comfort and versatility. The ergonomic stand allows you to adjust height, tilt, and swivel for the perfect viewing angle. You can also mount it on a wall for a clean setup. Multiple connectivity options make the ViewSonic 27″ 180Hz Gaming Monitor easy to use. It includes HDMI and DisplayPort, allowing you to connect to gaming consoles, PCs, and more. With a sleek, modern design, this monitor enhances any gaming setup. The narrow bezels create a seamless multi-monitor experience. Enjoy distraction-free gaming with an immersive display. Upgrade your gaming experience with the ViewSonic 27″ 180Hz Gaming Monitor. Enjoy smooth performance, fast response times, and stunning visuals. Specifications: Display : 27″ IPS Resolution : 1920 x 1080 FHD Refresh Rate : 180Hz Response Rate : 1ms MPRT
Are you looking for a high-performance monitor to boost your productivity? The MSI Pro MP251P 25″ 100Hz Monitor is the perfect choice. This monitor offers stunning visuals and smooth performance for both work and entertainment. Firstly, let’s talk about the display quality. The MSI Pro MP251P features a 25-inch screen with a 100Hz refresh rate. This ensures crisp, clear images and reduces motion blur. Whether you’re working on detailed design projects or enjoying your favorite movies, the visual experience is exceptional. Moreover, the 100Hz refresh rate provides a smooth and fluid viewing experience. This is especially beneficial for gaming and video playback. You won’t miss any details with this monitor’s high refresh rate. In addition, the MSI Pro MP251P is designed with productivity in mind. Its wide screen provides ample space for multitasking. You can easily open multiple windows and work on various tasks simultaneously. This helps in improving your efficiency and workflow. Furthermore, this monitor is equipped with anti-flicker technology and a blue light filter. These features reduce eye strain, allowing you to work for longer periods without discomfort. It’s a great choice for those who spend long hours in front of the screen. Connectivity options are also plentiful with the MSI Pro MP251P . It includes multiple ports such as HDMI and DisplayPort, making it easy to connect to different devices. This versatility enhances your overall user experience. In conclusion, the MSI Pro MP251P 25″ 100Hz Monitor is an excellent investment for anyone seeking to improve their productivity and enjoy stunning visuals. Whether for work or entertainment, this monitor delivers on all fronts. Elevate your workspace with the MSI MP251P today! Specifications: Display : 24.5″ IPS Resolution : 1920 x 1080 (FHD) Refresh Rate : 100Hz Response Rate : 1ms MRPT
Original 13.3-inch Retina LCD display (Space Gray) for MacBook Air A2337 (2020), pulled from a working unit. OEM part, ready to replace cracked or faulty screens with perfect fit and optics. This is a genuine Apple Retina display assembly removed from a working MacBook Air (model A2337, 2020). It’s ideal for repairing a damaged or nonfunctional screen on a matching model, delivering original visuals without resorting to aftermarket knockoffs. Key Features & Functionality True OEM Retina panel with factory calibration Integrated display glass, backlight, and flex cable Designed for model A2337 (Late 2020, M1) iFixit+1 Space Gray finish to match original chassis Tested: Display, backlight, no dead pixels (unless noted) Drop-in replacement requiring alignment and cable reconnection Specifications Important Notes & Considerations Must use exact model A2337 — other models are incompatible Slight blemishes or dust might exist due to being a used part Handle with care: screen glass is fragile Professional installation recommended if you’re not experienced
The MSI MAG 255PXF 24.5″ 300Hz Gaming Monitor is built for competitive gamers. It delivers ultra-fast refresh rates and smooth visuals for an edge in every game. Firstly with a 24.5-inch Full HD IPS panel, this gaming monitor offers vibrant colors and sharp details. The 300Hz refresh rate ensures ultra-smooth gameplay, reducing motion blur and screen tearing. Every movement is displayed with precision, making it perfect for fast-paced games. Furthermore the MSI MAG 255PXF features a 1ms response time, minimizing ghosting and input lag. This ensures every action is instantly reflected on the screen. Whether you’re playing FPS, racing, or eSports games. Moreover with Adaptive Sync technology, the display eliminates screen tearing and stuttering. This provides a seamless visual experience, even during intense gaming sessions. Also the monitor comes with wide viewing angles, ensuring consistent colors from every perspective. Its high color accuracy makes it suitable for content creation and video editing. The MSI MAG 255PXF 24.5″ 300Hz Gaming Monitor is designed for comfort and flexibility. It has an adjustable stand that allows tilt, swivel, and height adjustments. This ensures the best ergonomic setup for long gaming sessions. With multiple connectivity options, including DisplayPort and HDMI, this monitor is compatible with PCs, consoles, and gaming laptops. Plug and play with ease and enjoy lag-free visuals. Finally the monitor also features anti-flicker and low blue light technology, reducing eye strain. This allows you to game for longer without discomfort. In conclusion, the MSI MAG 255PXF 24.5″ 300Hz Gaming Monitor is the perfect choice for serious gamers. With ultra-fast performance, vibrant visuals, and ergonomic design, it provides a competitive edge in every game. Specifications: Display : 24.5″ Rapid IPS Resolution : 1920×1080 FHD Refresh Rate : 300Hz Response Rate : 0.5ms Speaker : 2W x2
HP E27q G5 QHD Monitor Firstly, the HP E27q G5 monitor is your gateway to an enhanced visual experience without breaking the bank. Whether you’re working, gaming, or indulging in multimedia content, this monitor has you covered. Secondly, one of the standout features of the HP E27q G5 is its Quad High Definition (QHD) display. This means you can enjoy crystal-clear visuals with sharp details for a wide range of tasks. The 27-inch screen size provides a generous canvas for all your computing needs, from productivity to entertainment. You get more screen real estate to enhance your multitasking capabilities. With a sleek and modern design, the E27q G5 monitor is a stylish addition to any workspace. It effortlessly blends with your existing setup, adding a touch of sophistication. Adjusting the monitor to your desired height is easy, thanks to its ergonomic design. Achieve the perfect viewing angle for comfort during extended work or gaming sessions. Connecting the HP E27q G5 is a straightforward process, and it’s compatible with standard ports for quick setup. No need to deal with complicated installation procedures. This monitor is a cost-effective choice for professionals, gamers, and multimedia enthusiasts. It offers top-notch features without straining your budget, making it an excellent investment. Specifications: QHD (2560 x 1440) 1000:1 5ms GtG (with overdrive) IPS
OEM-quality touchpad replacement for MacBook Air 13.6″ (Model A2681, 2022)—available in Gray, Gold, Silver, and Blue to match your original chassis color. Precision-engineered for seamless Force Touch performance and smooth gesture control. Compatible With: MacBook Air 13.6-inch (2022, Model A2681) with M2 chip—includes all color variants: Space Gray, Gold, Silver, and Midnight Blue. Part Type: Touchpad only—does not include the flex cable, connector, or mounting brackets. Intended for technicians reusing the original cable or transferring it during repair. Color-Matched Finish: Available in all four official A2681 colors to maintain aesthetic consistency with your MacBook’s lower case. Force Touch Support: Full compatibility with Force Touch gestures, haptic feedback, and multi-touch functionality (requires original Taptic Engine and logic board). OEM Build Quality: Matches Apple’s original surface texture, curvature, and responsiveness—ensures consistent click feel and tracking accuracy. Installation Note: Requires careful transfer of the original flex cable and Taptic Engine (if not already attached). Full bottom case disassembly is necessary. Recommended for professional repair technicians.
Specification Details Specification Details Input/Output Other Sound Mode Standard Mode Category Speakers Use Home Tweeter Type Cone Control Volume Control, Playback Bluetooth Version 5.0 Input Power (W) <25 W Active Noise Cancellation Passive Voice Control No Output Power Other Waterproof Yes Support APP No Support Memory Card Yes Material Plastic Playback Function MP3, FLAC, ALAC Remote Control No Support Apt-X No Intelligent Personal Assistant Apple’s Siri Display Screen No Built-in Microphone Yes Audio Crossover Full-Range Number of Loudspeaker Enclosure 1 Power Source DC, Battery, USB PMPO 40 W Channels 2 (2.0) Feature Phone Function, Play Video Battery Yes Communication Bluetooth, Audio Line Speaker Type Portable Cabinet Material Plastic Brand Name Bigmzpai Origin Mainland China Bluetooth Version V5.0 Waterproof Level IPX6 Battery Capacity Power Battery 10000mAh Brand YIBOLANG
The Dell P3424WEB Pro Plus 34″ 4K 60Hz Video Conferencing Monitor delivers a large, immersive screen ideal for work, meetings, and multitasking. You get a wide curved display that fills your field of view. It lets you open many windows side by side for improved productivity. Moreover, the Dell P3424WEB Pro Plus 34″ 4K 60Hz Video Conferencing Monitor includes a high-quality built-in webcam. The camera captures sharp and clear video for meetings. Integrated microphones and speakers provide clear sound without extra devices. This makes virtual calls simple and effective. In addition, the monitor supports USB-C with up to 90W power delivery. You can connect and charge a laptop with a single cable. This reduces desk clutter and simplifies setup. It also supports HDMI, DisplayPort, Ethernet and multiple USB ports for many devices. Furthermore, the Dell P3424WEB Pro Plus 34″ 4K 60Hz Video Conferencing Monitor uses a wide IPS curved panel with great color accuracy. Colors stay vivid and natural from wide viewing angles. This is useful for design work, video editing, or media viewing. The large screen enhances focus and comfort. Also, the monitor includes adjustable stand for height, tilt, and swivel. You can adjust it to a comfortable viewing position. The thin bezels and modern frame give a clean, professional look to any office space. The curved shape reduces glare and eyestrain during long hours. Overall, the Dell P3424WEB Pro Plus 34″ 4K 60Hz Video Conferencing Monitor combines a large display, smart connectivity, and built-in conferencing tools. It improves productivity, simplifies video calls, and enhances work comfort. This monitor is ideal for professionals, remote workers, creators, and teams needing an all-in-one display solution. Specifications: Display : 34″ IPS Resolution : WQHD 3440 x 1440 Refresh Rate : 60Hz Response Time : 8ms Curvature : 3800R
