I own Fenix L2D CE, Fenix L1T and Quark AA2 lights. They're very similar in fit and feel. Although their internal design looks like they came from the same production line, parts like tailcaps are on a different diameter -- the Quark is bigger. Both are waterproof to IPX-8 standards, both came with spare O-rings. The Quark light has a newer Cree LED, but that's to be expected since it's a later model.