This replaceable long-life lithium battery powers the Defibtech AED's self-checks and lasts up to 5 times longer than ordinary alkaline 9V batteries (and 10 times longer than carbon-zinc batteries).

The Ultralife brand battery has the highest energy density, flattest discharge voltage curve, longest shelf life, widest operating temperature range, and lightest weight of any comparable 9-volt battery. The UL-recognized Ultralife 9-volt lithium battery contains no mercury, lead or cadmium and has a patented safety mechanism.