5.25 overall. Water resistant. Tailcap switch. Impact resistant. LED. Modes: High (320 lumens, 2.75h runtime), Low (15 lumens, 45h runtime). Precision micro-textured reflector. 187m beam distance. Polycarbonate window. Black Nitrolon body with aluminum bezel. O-ring and gasket sealed. Requires (2) CR123A batteries (included). Clam packed.