SOL300 Plus bike headlight is the perfect solution for the most common challenge commuters: Being seen. GUEE SOL 300 Plus provides a powerful 300 lumens of light output but also features a unique auto light sensor (SAS) that adjusts the CREE LED light output (from 50 to 300 lumens) depending on the amount of ambient light present. This ingenious feature extends the run time on each charge. The self-contained battery can be charged via Micro-USB and as it is tool-free for easily be removed whenever you leave your bike. This bicycle headlight is compatible with the GUEE G-Mount and GUEE i-Mount.