Chamberlain 4228 EverCharge replacement Battery- 12v 4.5ah/ 12v 5ah- 2 PACK UPG # D5741 UB1250 12V 5Ah. Pack of 2 Dimensions: 3.54 inches x 2.76 inches x 4.21 inches. Weight: 3.09 Lbs SLA/AGM maintenance free, spill proof battery Rechargeable battery that can be mounted in any position, resists shocks and vibration 1 Year Warranty