Duracell Secure Digital High-Capacity (SDHC) is designed to enhance the performance of high-quality still and video cameras. SDHC cards from Duracell Flash meet all the standards of the SD Card Association 2.0 Specification for SD cards larger than 2 GB. Although identical in size to a standard SD card, SDHC cards are different and are only compatible with devices designed for SDHC. Please check the Owner's Manual of the intended device to verify that it is SDHC compatible. Also note that SDHC requires an SDHC-compatible card reader (such as a Duracell 6-in-1 or 15-in 1 Card reader) and is not backwards compatible with most older card readers. Duracell SDHC cards offer Class 4 ratings, describing their optimal data-write transfer speed of 4 MegaBytes per second.