Keenstone 9V Li-ion battery is non-toxic, without memory effect and environmental friendly. Cycles life can be up to 500 times. 9V 800mAh rechargeable li-ion battery with 3 packs, higher capacity than ordinary 9V battery, more affordable and environment friendly. These batteries provide the correct amount of current and voltage, seem to last longer than the Duracells. And I never have to worry about running out of batteries.