With the SanDisk Extreme 400GB microSD UHS-I Memory Card get extreme speeds for fast transfer, app performance, and 4K UHD video. Ideal for your Android smartphone, action cameras or drones, this high-performance microSD card handles 4K UHD video recording, Full HD video and high-resolution photos. The super-fast SanDisk Extreme microSDXC memory card reads up to 160MB/s and writes up to 90MB/s. Plus, it's A2-rated, so you can get fast application performance for an exceptional smartphone experience. Not all devices support microSD memory card formats. Check with your device manufacturer for more details. For 128GB-400GB: Up to 160MB/s read speeds, engineered with proprietary technology to reach speeds beyond UHS-I 104MB/s, requires compatible devices capable of reaching such speeds. Up to 90MB/s write speeds. 1MB=1,000,000 bytes.