SanDisk Extreme SDXC 256GB

256GB: Up to 180MB/s read speed. Engineered with proprietary technology to reach speeds beyond 104MB/s, require compatible devices capable of reaching such speeds Up to 130MB/s write speed. Based on internal testing; performance may be lower depending upon host device, interface, usage conditions and other factors. 1MB = 1,000,000 bytes. 1GB = 1,000,000,000 bytes. Actual user storage less.