Smart Rear Light Rear Lights Bicycle Flashlight Dual Work : Intelligent speed detection: when delay is detected, the rear light increases brightness to high brightness for 3 seconds, alerting the vehicle in the rear 6 of these lights: flash, fast flash, strobe, flickering breath, eco flash and constant USB battery: rechargeable bike tail light built-in lithium-ion 350 mAh, rear light lasting 10-35 hours full charge 2,5 hours Made of aluminium and ABS plastic, waterproof and shockproof Dual operating modes: this bike tail light can double click to switch between manual/automatic mode Specification: Type: High Brightness Rear Lights Power supply: USB mAh lithium-ion battery : red Charging: about 2,5 hours to fully charge, 10-35 hours Light modes: constant/flash (total 6) sizes: Size: . 31,3x28,3mm/1,23x1,11 inch contains: 1x instruction 1x charging 1x bracket 1x seat; 1x gasket 1x bicycle tail light;