Designed for microsd devices such as smartphones, interchangeable-lens cameras, drones, or gopro action cameras that can capture full hd, 3d, and 4k video, as well as raw and burst photography, the 64gb extreme uhs-i microsdxc memory cardfrom sandisk has a capacity of 64gb, is compatible with the uhs-i bus, and features a speed class rating of v30, which guarantees minimum write speeds of 30 mb/s. If your device does not support the v30 standard, this card also supports the u3 standard, which also guarantees minimum write speeds of 30 mb/s. Read speeds are supported up to 160 mb/s and write speeds max out at 60 mb/s.