This light weight 2-cell battery pack is ideal for use on your helmet. When combined with either the TITAN LED or XERA LED you can run the lights on HIGH mode for 2 hours. All batteries come with an on board coefficient thermistor to detect high temperatures. As a safety feature the power is shut off if temperatures ever get too high. The battery pack is built with the highest grade lithium-ion battery cells produced by Samsung. Use the Velcro strap to attach your battery to your frame or handlebars.