... -171 head lamp Use the safety, no pollution, no memory lithium-ion battery, and the capacity is up to 2400mAH; KM-171 head ... the safety, no pollution, no memory lithium-ion battery, and the capacity is up to 2400mAH;2. lithium-ion battery built-in overcharge & over discharge protection ... . It cycles like this .Cautions:For service life of the battery, when the ray of the head light is becoming dim ...