Pro-level features for pro-level activities, all in an ultra-compact design. Experience complete control over lighting thanks to Constant Mode, Pass Thru + Charge and 8 different lighting modes, allowing you to see and be seen on your next adventure. BioLite's 3D SlimFit construction integrates electronics directly into the headband, creating a flush, low-profile front that won't wobble. The rear mesh panel distributes weight and keeps pressure off your forehead, while the moisture-wicking band keeps you cool and dry. The pro feature: constant mode. Most headlamps automatically regulate luminosity to conserve battery life, dimming over time as the eye gets used to the dark. This works well in many cases, but should not be the only mode available for technical terrain or complete darkness. Constant mode gives full control over the lumens and allows you to set a constant brightness level that will not dim - unless commanded to do so with the push of a button. Pro feature: Run forever. As a rechargeable headlamp, the Headlamp 800's operating time can be extended indefinitely thanks to Pass Thru+ charging. This means that the headlamp can be used while charging at the same time.