High lumen tactical light that is USB rechargeable, so you can charge on-the-go using almost any USB source. It also accepts multiple battery sources to use as a back up so you'll always have power when you need it. Choice of three user selectable programs: high for maximum illumination - medium for bright light and longer run time- Low for less intense beam and extended run time, and also a strobe for signaling or disorienting. Self adjusting battery cradle secures multiple battery sizes and eliminates battery rattle. Rechargeable using supplied USB cord or optional AC wall adapter. Water-resistant sliding metal sleeve protects USB port. Durable anodized aluminum construction with IPX4 water resistant and 1 meter impact resistance tested. Anti-roll head prevents the light from rolling away when you set it down.