Surefire Flashlight G2X Pro Dual-Output LED Flashlight Weatherproof Virtually indestructible LED emitter regulated to maximize light output and runtime Two output levelshigh for maximum light, low for extended runtime Precision micro-textured reflector creates smooth, optimized beam Tough polycarbonate window resists impact; Tough Nitrolon body, anodized aluminum bezel Dual-output tailcap click switchpress for momentary-on low, click for constant-on low, return to off then press or click again for high; WeatherproofO-ring and gasket sealed; Includes high-energy 123A batteries with 10-year shelf life