Black Diamond Cosmo Headlamp One DoublePower LED and 2 SinglePower LEDs provide 55 Lumens (max setting) Ultra-compact design uses 3 AAA batteries to allow up to 100 hours on the DoublePower or 140 hours on the SinglePower LED settings. IPX 4 water resistance rating Single power switch toggles between long range single DoublePower LED mode, proximity dual SinglePower LED mode, off, and controls the dimmer function.