Remember when you didn't depend on cords & gasoline to run your tools? power your life with a WEN 40V Max lithium-ion 4Ah rechargeable battery. Compatible with the WEN 40V quick charger (model 40400), this battery is designed to fit the entire WEN 40V line, including the WEN leaf blower & the WEN chainsaw. Lithium-ion cells create a fade-free power supply that provides 4 amp hours worth of steady & consistent operation. An onboard battery meter informs users when their power supply is running low & in need of a charge. Replace your current battery or add an extra for double the work time, keeping one on the charger & one in the Machine. Forget the hassles of Extension cords & gasoline. It's time to simplify your life with a WEN 40V Max lithium-ion 4Ah rechargeable battery. Remember when your yd work was easier than ever before? remember WEN.