Security system batteries are used to provide back-up power when the AC mains power fails. Generally speaking, an alarm (security system) battery will provide anywhere from 30 minutes to several hours of backup power during a power failure. But alarm batteries should be replaced every 2-3 years on average so they are ready when they're needed. Otherwise you may find that your alarm system will fail prematurely during a power outtage.
These alarm batteries are suitable for use in systems from DSC, GE, Interlogix, Honeywell Vista, ADT, Chubb, Rogers.
When looking for a replacement battery, the main consideration is the size, voltage, capacity (AH rating) and terminal type. Most standard alarms use 12V batteries. The most popular size is 4AH or 4.5AH which are interchangeable. The next most common size is 7AH or 8AH which are also interchangeable. Larger batteries allow your alarm system to run longer when power fails. An alarm battery typically has an F1 187 faston tab which is 0.187" or 4.75mm wide.