The 12v 5ah battery is the most popular battery for UPS units. Among these, Universal Power Group’s UB1250 battery is by far the leader. The UB1250 has F1 Terminals, meaning these are about half the size of the broader F2 terminals. Some photos of these Universal Battery products can be found below:
12v 5ah
The above replaces the old blue colored battery seen below:
The UB1250 12 volt 5 amp hour battery can be purchased at http://www.apexbattery.com/universal-battery-ub1250-ups-battery-ups-batteries-universal-battery-ups-batteries.html
1-855-888-2739 (Mon - Fri 9 a.m. - 7 p.m. EST)