1. Battery: CR2032 (included), working for about 100 hours.
2. The vel. design on back of light can be attached on the helmet, tactical vest and etc.
3. 2 Light modes: always on and flashing.
4. Waterproof and battery can be replaced (***Note: you need to use your knife to open the gel for replace the battery and then fix it with glue, but the waterproofness will be affected).
5. Perfect for cycling, Diving, CS, Wargame, Shooting and other outdoor sports for teammate identification and survival signal etc.