Energizer MAX, 4 Pack, 9V, alkaline batteries, hanging multi pack. Long-lasting power and innovation is what the Energizer MAX family is all about. Energizer 9 Volt batteries hold power for up to 5 years while in storage, so you have power when you need it most. When it comes to smoke detectors, toys, remote control cars, clocks, and other valuable devices, you can feel confident knowing you have the long-lasting power and protection you expect from Energizer.