The Kryptonite Alley Front and Avenue Rear Bike Light combo makes riding at night safer and simple. Both lights feature a multi-fit quick release system that allows tool-free mounting on the handle bars/bike frame (Fits bars 10-32mm in diameter). The front Alley F-275 boasts an impressive 275 lumen beam with a 149m range. On full blast the battery will last 2.5 hours. The rear Avenue R-19 puts out 19 lumens and has a 1 hour battery life. The built-in battery indicator with show red when battery is lower than 25% and blue when the batter is fully charged.That's right, no need to worry about swapping batteries. Both lights are rechargeable and come with a USB charging cable. This allows the Alley and Avenue to cut out heavy and bulky batteries. If you get caught in the rain, don't worry. These lights are water resistant and built ready for anything you throw at them! Don't get caught riding in the dark. Light up the night with Kryptonite!