Ultra II SD Plus USB 512MB with Minimum of 10MB/second sequential read speed for ultra-fast image viewing and data transfer, Minimum 9MB/second sequential write speed lets you capture large image files faster, and Low power consumption for longer battery life Note: 1 megabyte/ MB equals 1 million bytes/ 1 gigabyte/ GB equals 1 billion bytes. Some of the listed capacity is used for formatting and other functions, and thus is not available for data storage.