The PowerSonic PS-640 is a 6V, 4.5Ah Rechargeable Sealed Lead Acid Battery. The PS-640-F1 uses .187 terminals, also known as F1 terminals. This battery is used in a variety of applications, including Burglar Alarm Systems, Access Control Systems, Fire Alarm Systems, and virtually any other application that requires a 6 volt, 4.5Ah SLA battery. Also known as -Power-Sonic PS-640 6V/4.5AH Sealed Lead Acid Battery-F1 Terminal-Power-Sonic 6V 4.5AH SLA BATTERY - PW-PS640F1