Magicshine Bike Light Battery, MJ-6102 high Capacity 6 Cell Li-ion Rechargeable Battery for Bike. 7800mah Waterproof Battery for Mountain Bike Lights | Round Plug Magicshine Rechargeable Bike Light Battery Pack MJ-6102, 6 cell 7.2V 7800 mAh capacity. Compatible with all Magicshine bike lights with round plug, Comes default with MJ-906. For use with Magicshine 8 series bicycle lights, adapter cable MJ-6078 is needed. The battery is more ergonomic and straps neatly to your frame using two nylon straps The new waterproof battery compartment design and high quality and large area silicone non-slip mat All Magicshine batteries include BMS with over-charge, over-discharge, over temperature and short circuit protection meaning you can be sure that your Magicshine battery is safe to use and charge.