Buying Incompatible SD Cards. All microSD cards fit into all microSD card slots, but they don't all work. ... The three main formats, which you're probably already familiar with, are SD, SDHC, and SDXC (or microSD, microSDHC, and microSDXC—micro and full-size cards are based on the same spec). The fourth format is SDUC.Dec 19, 2018
