USB Rechargeable with Battery Indicator: The XL400 bike headlight uses a MicroUSB charging port and a 2200mAh battery, eliminating the need for battery replacement. It boasts approximately 2.5 hours of battery life at 400 lumens and approximately 5 hours in low-light or flash mode. An indicator shows real-time battery life, making it easy to plan your charging schedule. Dual Mount and Compatible: A bike computer mount is not included. If you prefer a reverse-mounted mount, you must purchase a bike computer mount with a GoPro light mount. The XL400 supports both forward and reverse mounting and comes with a bike computer mount for reverse mounting. Sidelights and Aluminum Housing: The design incorporates side warning lights for enhanced side visibility and comprehensive rider protection. Easy Operation and Simple Installation: Five modes are available: high, medium, low, flash, and SOS. A long press turns the light on or off, and a short press switches modes. Easily mount on your bike using the included light mount. Practical Use Cases: 1) For nighttime commuting on city streets, 400 lumens of brightness provide a clear view forward, and the battery life is sufficient for regular riding. 2) For off-roading or on dimly lit trails, the long battery life in medium and low brightness modes helps you complete your ride safely. 3) When riding in low visibility or mixed traffic, the sidelights and wide heat dissipation area help other road users notice you.