Optronics STL43RBXP is for the STL43 Reflex Flange Series. This is a Red 4" Round Sealed LED Light with Red Reflex Mounting Flange and gasket. This is a sonically sealed and waterproof light comes as a standard PL-3 connector. The Flange mount helps with security and theft reduction. The reflex flange meets SAE A for reflector.