Knog POP R rear light. Exceptional quality for value for money. Super bright, AA battery-powered, long runtimes, replaceable straps, and side illumination.

Specs:

OUTPUT: 5 lumens
DIMENSIONS : 25 x 25x 70 mm
WEIGHT : 53g
MATERIALS : PC-ABS plastic housing and polycarbonate lens.
BATTERY : 1x AA Battery