Serfas True Lumen TSL-1000 Rechargeable Headlight system for the front of your bike or helmet. You get five super bright lighting 1000 lumen modes: over drive, high, medium, low, flashing. Up to 3.5 hours runtime in over drive mode. Ram Air Vent Cooling System. Water resistant, horizontally and vertically adjustable, and has a battery indicator. Comes with rechargeable lithium ion fuel cell, charging unit, helmet mount, battery extension cable, and its own transport pouch. Ideal for commuters or anyone who rides at night.