PETZL - REACTIK+ Headlamp, 300 Lumens, Bluetooth Enabled REACTIVE LIGHTING TECHNOLOGY: headlamp automatically adjusts brightness to the needs of the user, offering a maximum of 300 lumens ENERGY EFFICIENT: enjoy a longer burn time as the headlamp beam automatically adjusts brightness to the user's specific needs 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