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 in sotrage and they will hold a charge for up to 1 year when not in use. These powerful NiMH batteries work in any NiMH charger and you can recharge them up to 400 times. or up to 400 recharges, whichever comes first.