? Digitally Regulated for Constant Brightness ? Low Battery Indication ? Uses two CR123A battery (not included) ? 11.4cm (L) x 2.1cm (D) (or 4.5 in (L) x 0.8 in (D)) ? Made of aircraft grade aluminum ? Durable Type III hard anodized finish ? 50g (or 1.7 oz) weight (excluding batteries) ? Waterproof to IPX-8 Standard ? Toughened ultra clear glass lens with AR coating ? Push-button tailcap switch ? Capable of standing up securely on a flat surface to serve as a candle ? Battery not included ? Includes a holster, a lanyard, two spare o-rings, and a rubber switch boot. Operation Fully press to switch on and turn the bezel to select the General Mode or the Turbo Mode. A soft-press anytime while the light is on will change the brightness levels of a certain mode. Keep the light off for over 2 seconds and the light will turn completely off, restoring the regulation circuit to the default setting.