The 64GB Extreme PRO UHS-I SDXC Memory Card from SanDisk is designed for SD devices that can capture Full HD 3D and 4K video as well as raw and burst photography. It has a capacity of 64GB is compatible with the UHS-I bus and has a speed class rating of V30 which guarantees minimum write speeds of 30 MBs. If your device does not support the V30 standard this card also supports the U3 which provides minimum write rates of 30 MBs. Read rates are limited to 200 MBs while write speeds are limited to 90 MBs. A built-in write-protect switch helps to protect card data from unintentional erasure.