2 cell battery built from 2 Panasonic 3400mAh 18650 Li-ion batteries in a hard-shell case.

4.5oz (128g), 2.0"x 1.75"x 1.3"

8 Stage built-in fuel gauge displays remaining power. 

Will work with all Gloworm Gen 1 lights, Gemini, and Magicshine bike lights (except MJ-880)

*Not compatible with Gloworm G2.0 lights

Includes velcro attachment strap.