Product name: New LED rear bike light P717
1) Product size:Dia.27.3x34mm
2) Material: plastic
3) Light bulb:1 super bright LED
4) USE:2CR2032 battery included
5) Switch Function1: 2LED ON- flashing-off ,
6) Working time: more than 24 hours
7) Features: Tool free installation
Seat post 20-36 mm
Quick release mount bracket for bicycle light