Gloworm's 6800mAh 4-cell battery pack is built of 4 of the best Panasonic 18650 Li-ion cells enclosed in a hardshell case and includes a built-in fuel gauge. 

8.2oz (232g), 3.0"x 1.75"x 1.75"

The same size and weight as the 5800 4 cell pack

Works with all Gloworm Gen 1 lights and also all Magicshine and Gemini lights and many others.

*Not compatible with Gloworm G2.0

Attaches to the bike with an included velcro strap.