Knog Plus Rear Road Bicycle Light + USB Rechargeable, Black, The Knog Plus rear bike light is a super-bright, 100% waterproof and totally versatile USB rechargeable bicycle light. Mount the light to your seat-post, seat stays, and pannier racks, or use the integrated wearable clip to attach the light to your t-shirt or backpack. More of a runner than a cyclist? No dramas. The Plus light also doubles up as a wearable night running light. Just attach the light to your t-shirt, shorts, socks or headband using the smart integrated clip. With an output of 20 lumens and a run time of up to 40 hours in eco flash, the Plus ensures you are well seen to all other cyclists, road users and trail runners all night long.