Duracell Rechargeable Pre-Charged NiMH batteries let you charge hundreds of times helping you save money. With its Ion Core technology you get amazing power in every battery. Plus they come pre-charged and ready to use. They are guaranteed to last for 10 years (or up to 400 recharges whichever comes first) in storage and they will hold a charge for up to one year when not in use. These powerful NiMH batteries work in any NiMH charger and you can recharge them up to 400 times.