With very few exceptions anything 510 will work, the number refers to the size of the connector and type of threading. If you want more options several sites sell adaptors (madvapes is one I believe) to use different equipment (ex. 510 to 808 or so on). But the 510 is a good choice as there are tons of accessories for them, and many of the bigger/fancier mods use 510 connections so you don't have to buy new att's etc if you get a new e-cig.