Waterproofing design -adjustable base is provided for each head lamp, with back and forth inclination -model of battery required: 2x 18650 -t6+2r5 led chips, as bright as a spotlight. if the option contains battery: about 18650 battery - brc 18650 3.7v 5000mah rechargeable protected li-ion battery - over temperature and over current protection - short-circuit protection & environment friendly - widely used on torch, laser pointer, as emergency lighting and other portable devices about the 18650 battery charger- how to know the battery full charged