"HC" simply means higher capacity. SD and SDHC cards will also have a "class" number (shown on the face of the card in an open circle) which indicates how fast data can be written or read to/from the card. Class numbers range from 2 upwards. Bigger numbers mean faster data handling--important in digital cameras and other high performance electronics, but unimportant for a finder. Before buying a new SD card, scavenge old electronic devices you've put aside (especially retired digital cameras) and you may find a perfectly good SD card for free!