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 for 10 years* in storage 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.