SanDisk Corp. has doubled the capacities of two of its SanDisk Ultra II line of flash memory cards with the addition of the 4GB Memory Stick PRO Duo card and the 2GB SD Plus, which also includes a USB connector for rapid transfer of photos or other data without a separate card reader.

Each SanDisk Ultra II card features a minimum write speed of 9MB per second and a minimum read speed of 10MB per second. The fast write speeds are designed to take advantage of advanced digital camera features such as rapid fire, continuous-shooting modes and video clips.

The SanDisk Ultra II Memory Stick PRO Duo is priced at $59-$119 for the 512MB-2GB, and $239 for the 4GB. The SD Plus 512MB card carries a $69 price tag, while the 1- and 2GB are $89 and $134, respectively.