FIAMM replacement battery for SAI APC RBC 55, 12V, 18Ah/216Wh, Lead-Acid, rechargeable, 181mm x 76mm x 167mm, Original New - AliExpress Consumer Electronics
Amazon.com: FIAMM FG21803 12V 18Ah Sealed Lead Acid - AGM - VRLA Replacement Battery : Health & Household