Knog pop r rear lightwhat some love might not be so loved by others so instead of compromising knog have made 10x designs for three lights some are mild some are wild but the striking form does not outshine the excellent function super bright aa battery powered long runtimes replaceable straps and side illumination featuresmaterials pc abs plastic housing and polycarbonate lenslight output 5 lumensdimensions 25x25x70mmbattery 2x aa batteryrun time 7 hrs steady 200 hrs eco f