SanDisk Mobile Ultra MicroSDHC UHS-I for Android Perfect for today's high-performance Android and other smartphone and tablet users, SanDisk Mobile Ultra cards deliver faster transfer speeds of up to 30MB/s for faster multi-tasking and app response times. Plus, get twice the speed for shooting photos and Full HD video with a Class 10 rating (class 6 for 4 GB. & 8 GB. capacities)Up to 30MB/s read speed write speed lower. Based on internal testing performance may be lower depending upon host device. 1 megabyte (MB) 1 million bytes. Compatible device required. Full HD video (1920x1080) and HD (1280x720) video support may vary based upon host device, file size, resolution, compression, bit rate, content and other factors.