3 3/8” overall. Intensely bright, virtually indestructible tactical light. Black anodized finished machined aluminum sealed construction. Features user programmable strobe enable/disable. C4 LED with blinding beam (160 lumens) with optimum peripheral illumination-will not break or burn out! Rail grip clamp system securely attaches/detaches quickly and safely with no tools and without putting your hands in front of the muzzle. Waterproof to one meter for one hour, dustproof. Ambidextrous momentary/steady on-off switch. Double tap of momentary paddle within 0.4 seconds activates strobe. Fast, adjustable, secure side mounting. Includes Rail Locating Keys for Glock style, 1913 Picatinny, S&W 99/TSW, and Beretta 90two. IPX7 rated design. Powered by two 3v CR123A lithium batteries with 10-year storage life (included). Runtime: up to 2 1/2 hours. Weighs: 4.18 oz. Gun not included.