Simply The Right Card More space and higher speed. Free up your devices with the largest capacity and highest read/write speeds in its class, perfect for 4K UHD video. *4K UHD video support for 512GB, 256GB and 128GB cards. Host device compatibility may vary* *The foregoing read write speeds are based on internal tests conducted under controlled conditions. Actual speeds may vary depending upon card capacity* Extreme endurance for monitoring devices Capture your crucial moments in high-resolution, even in harsh conditions. Engineered to deliver long lasting performance, the Samsung is a perfect fit for Surveillance, dash cams and body cams. Get peace of mind with video recording you can rely on. Extended Compatibility Critical data Safeguarded Compatible with a wide range of devices for both SD and microSD. You can even capture detailed 4K UHD video. The included SD adapter fits most devices under almost every brand name. About capacity: ·64GB?58GB-60GB ·128GB?119GB-120GB ·256GB?228GB-235GB ·512GB?455GB-470GB ·This is calculation difference between manufacturer and our PC?1MB=1000KB) , please Google 'Memory card capacity' to get more information. About speed: The read and write speed marked on the package: It is demonstrated by internal testing under certain controlled conditions using the UHS-1 interface. The actual speed may vary due to usage and other conditions. For products that are not compatible with the UHS-I interface, the speed may vary depending on the interface conditions? Steps to verify the capacity and speed of the memory card: (1). Please use quality USB 3.0 card reader to verify all memory card by H2testw on PC. Real memory card should pass H2testw with no error. (2). Please don\'t use cheap card reader to test Micro SD card, speed of Micro SD card will be reduced by low quality card reader. (3). Micro SD memory card speed is greatly affected by card reader and the capacity you choose , USB port etc. Low quality device will 100% slow down card speed,1MB=1000KB. *Transmission speed is based on Samsung's internal testing environment and conditions. The actual speed may vary depending on the host device and environment used. **For devices that do not support UHS-I, the transmission speed will vary due to interface limitations. The products we sell are genuine Samsung products: 1.The Samsung memory card verification service method was changed from “anti-counterfeit laser sticker” to “software verification”, and the product packaging has a V-shaped logo. 2.The new authenticity identification needs to be downloaded to Samsung's official website (Samsung official website - after-sales service - download center) to download software. *Samsung products are produced in the Philippines, China and South Korea; all products are original authentic products.