AJC 12V 18Ah Sealed Lead Acid - AGM - VRLA Battery: BatteryClerk.com Sealed Lead Acid
Mighty Max Battery ML18-12- 12 VOLT 18 AH SLA BATTERY- PACK OF 4 Rechargeable Sealed Lead Acid 12180 Backup Power Batteries (4-Pack) in the Device Replacement Batteries department at Lowes.com