Flexible Power Application with Carry-on Convenience! The Fenix BC21R Rechargeable Bike light is an integrated yet versatile bike light which delivers a maximum 880-lumen neutral white light. The BC21R features four output modes plus Flash to enhance your cycling activities. The built-in side red light assists in riding safety. The quick-release bike mount makes it easier to mount or dismount the light. Because the BC21R is powered by one standard 18650 rechargeable battery or two non-rechargeable CR123 battery, you can easily dismount the light, change the batteries, then continue on those long rights. This well-designed bike light goes anywhere for any activity. Perfect for road racing, bicycle riding, and urban commuting.