The 300 Lumens LED Headlamp with BatteryGuard™ stops battery drain so you'll have power when you need it most. Conventional headlamps experience residual power drain as long as batteries are connected to the circuit, even when the device is off. With BatteryGuard, batteries are automatically disengaged from the circuit when the headlamp is turned off to extend their life by as much as 25%. It also reduces the chance of damaging corrosion so batteries can be stored in the device for years (up to their inherent shelf life). Additional features include a fully adjustable head strap, a single on/off switch, water resistance, impact resistance up to 1 meter, and lifetime LED bulbs that never need replacing. No matter the situation, from power outages to roadside emergencies, this BatteryGuard headlamp with a 150-meter beam gives you Power When You Need It™.