Identification marker light,tacticals light with three modes of alway on,flashing turn off. ,helmet flashing light be made from good which with good sealing (waterproof) and flexibility. Powerful function,this tacticals light is essential item for your outdoor activities, such as cycling, hiking, hunting, diving. you can on your tacticals helmet, hangs it on it on your backpack, stick on your bicycles seats or hangs on your neck. Attention,when the battery is exhausted, you can replace the battery. (but changing the battery will affect the waterproof function of the product.) Wonderful ,sweet warm for friend family or yourself