One of the best features of Lezyne's XL series of lights is Infinite Light technology, which allows you to pop open the light and replace the batteries on the trail, effectively giving you as much power as you want to carry. In order to utilize this feature, however, you'll need backup batteries. Lezyne LIR 18650 Batteries are just what you need to keep the ride going beyond the wee hours of the night. Lezyne replacement batteries come in a machined aluminum tube with rubber end caps for storage and protection from moisture or dirt. The batteries are tested for capacity and quality before they leave the Lezyne factory. Lezyne LIR 18650 Batteries are compatible with Super Drive XL, Power Drive XL, Mega Drive XL, Super Drive, and Power Drive Headlights.