Main Features: Excellent durability: The Recognition Helmet flashlight operates in two modes, including normal glow and flashing Easy to use: you can hang your flashlight from your backpack, attach it to your helmet, attach it to your bike seat, or drape it around your neck. CR2032 button battery: it can last one week in steady on and one month in flashing (the actual time will vary according to the ambient temperature).The battery can replaced by itself after use, but it needs to replaced by cutting the silicone, so as to lose the waterproof wrap and pay attention to the edge of the battery to avoid the contact between positive and negative electrodes.