RBC10 equivalent. 12V 4AH rectangular battery with contacts on top. 12 Volt SLA UPS Battery. Fits models; APC BackUPS Office 250, APC BackUPS Office 280, APC BackUPS Office 280VA, APC BackUPS Office 350, APC BackUPS Office BF250, APC BackUPS Office BF280, APC BackUPS Office BF500, APC Office 280VA, APC Office BF250, APC Office BF280, APC Office BF500, Best Tec