The SDHC memory card is a highly secure stamp-sized flash memory card, which can be used in a variety of digital products: digital music players, handheld PCs, digital cameras, digital video camcorders, car navigation systems and electronic books. To support higher capacity needs, SD cards are now a different specfication which is called Secure Digital High Capacity (SDHC) and supports 4GB and up. Cards read and write data at numerous speeds. Many factors impede this performance. SDHC guarantees a minimum read and write speed necessary to handle recording high quality video and audio. The maximum card speed may vary, but you can always depend on SDHC cards to meet your SDHC host product’s high quality performance requirements. Because SDHC work differently (supports the new higher capacity cards) this new card format is not backwards compatible with legacy SD format host devices.