PETZL - REACTIK, 220 Lumens 220 LUMEN: maximum output REACTIVE LIGHTING TECHNOLOGY: headlamp automatically adjusts brightness to the needs of the user. MIXED BEAM: produced by the primary light source and activated with a light sensor RECHARGEABLE: no need to carry around extra batteries. Headlamp runs on an 1800 mAh Lithium-Ion battery with an integrated USB port for convenient charging WASHABLE AND ADJUSTABLE HEADBAND: this two-part system is constructed for optimal positioning during dynamic activities