The bell smart home battery pack is the perfect addition to your security & control panel that provides you with long lasting secure power. This battery pack can be used as a replacement for your existing battery. Battery features 7. 2v 2. 1ah nickel metal hydride (nimh) battery replacement battery for: lynx 3000, lynx 5100, lynx 5200, lynx 5210 includes instructions for the installation of your bell smart home devices