Virtually indestructible LED emitter regulated to maximize light output and runtime Two output levels high for maximum light, low for extended runtime Precision micro-textured reflector creates smooth, optimized beam Tough polycarbonate window resists impact High-strength aerospace aluminum body, Mil-Spec hard-anodized for extreme durability Dual-output tailcap click switchpress for momentary-on low, click for constant-on low, return to off then press or click again for high Weatherproof O-ring and gasket sealed Includes high-energy 123A batteries with 10-year shelf life