1. Size: 4 * 4cm // Weight: 12g
2. Package: Only Signal Light, NOT included helmet and helmet cover. //Back peeling sticker: It can be sticked on helmet.
3. Battery: CR2032 (included), working for about 100 hours.
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 game, Airsoft Game, Shooting, Hiking, and other outdoor sports.