* 3*Cree XM-L2(U2) LED,2000 lumens output * Uses 2*26650 batteries * Aircraft-grade high strength aluminum material * Over-discharge protection function * Mechanically tail rotary switch offers high reliability underwater * Water pressure resistant construction ,depth rated to 150 meters * High efficiency constant current circuit, constant brightness * Reverse polarity protection, to protect from improper battery installation * Alloy aluminum reflector with professional optical analysis * Premium Type III military hard-anodized seawater-corrosion-resistance finish * Toughened glass with high water pressure resistance under deep water