It tells you the speed at which it can transfer data. It matters if you are trying to do HD video recording. class 4 is second highest class. google it. I got it from SD association

Questions & Answers: Kingston 16GB Secure Digital High-Capacity (SDHC) Flash Card Model SD4/16GBET

Returns

& Orders

Black Friday Deals

Home
Components & Storage
USB Flash Drive & Memory Card
Memory Cards
Kingston Technology Corp.
Item#: N82E16820134971
Questions & Answers

(57)

double click image to zoom in

Shop All Kingston Technology Corp. Products

Kingston 16GB Secure Digital High-Capacity (SDHC) Flash Card Model SD4/16GBET

Class 4
16GB

Out of Stock