SDXC cards are slightly rectangular, with one corner cut at a 45-degree angle, and they look almost exactly like SD cards. SDXC cards measure 24 mm by 32 mm by 2.1 mm (0.94 x 1.26 x 0.08 inches).
Another type of SD card, SDHC (SD high capacity), allows storage capacities at 4 GB and beyond. SD cards are limited to 2 GB. Some older digital cameras that use SD cards cannot read SDHC or SDXC cards.