This is the back up battery for a hardwired system. If you have a metal box/control panel in a closet or basement that has a back up battery that looks like this chances are this is the same battery. It is meant to be a 24 hour back up battery but can vary for each system since some systems use more power than others. It should be replaced every 3-5 years to make sure that it continues to work properly and that you do not get annoying low battery messages on the screen and calls from the monitoring station. All that is necessary to swap it out is to unhook the black and red wires from the old battery and connect them to the new battery.