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 128GB Extreme UHS-I microSDXC Memory Card from SanDisk has a capacity of 128GB, 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 90 MB/s and write speeds max out at 60 MB/s.