Cardiac Science has designed a battery that works specifically with the Powerheart AED G3 by pairing the Intellisense battery circuitry with the Rescue Ready® technology in the AED. Years of research and technology has gone into delivering this dependable, medical grade lithium battery. From manufacturer to distributor, each replacement battery undergoes testing prior to be sold by Cardiac Science. Once the battery is in the G3 AED, it performs daily self-tests. This is non-rechargeable battery. The G3 AED will alert you when the battery power is declining and should be replaced.