BEAM - Shift between spot and flood beams for distance or up-close lighting needs. BATTERY - Choose between USB rechargeable battery or alkaline back-up batteries. BRIGHTNESS - Shift between high and low modes for bright light or longer run time. The Double Clutch USB gives you the flexibility of shifting between beams and modes to fit your task, as well as choosing your battery source. It is also easy to use, even with gloves - just a quick twist of the facecap turns the light on and off, or changes the output from spot to flood. C4 LED with spot and flood beams - both with high and low modes; remembers the last mode used when you turn it back on. Spot beam for some distance lighting: High/Spot: 125 lumens; 1,700 candela; 82m beam; runs 3.5 hours (lithium polymer); 6 hours (alkaline). Low/Spot: 30 lumens; 400 candela; 40m beam; runs 10 hours (lithium polymer); 18 hours (alkaline). Flood beam for work at arm's length: High/Flood: 125 lumens; 250 candela; 31m beam; runs 3.5 hours (lithium polymer); 6 hours (alkaline). Low/Flood: 30 lumens; 70 candela; 4m beam; runs 10 hours (lithium polymer); 18 hours (alkaline). Facecap twists for easy functionality, even with gloves. Dual-fuel: Powered by USB rechargeable lithium polymer battery; also accepts 3 AAA alkaline or lithium batteries as back-up. AC charge cord and adapter included. Lithium polymer battery features charge status indicator. Low-profile construction with optimized center of gravity provides maximum comfort and stability during use. 60-Degree tilting head reduces neck fatigue. Durable, impact-resistant polymer construction. Locking mechanism on battery compartment opens easily to recharge or replace batteries, but keeps the body from popping open if dropped. IPX4 water-resistant; 2m impact resistance tested. 4.03 oz. (114.25g) [with lithium polymer battery]; 4.69 oz. (132.96g) [with AAA alkaline batteries]. Includes USB cord, and adjustable elastic and hard hat straps; optional AC wall adapter available.