Amazon.com: Toyo 3FM4.5 6V 4.5Ah Sealed Lead Acid Battery - This is an AJC Brand Replacement : Health & Household
Mighty Max Battery Replaces cp0660 gp645 lcr6v4p hk-3fm4.5 wp4-6 Rechargeable Sealed Lead Acid 645 Backup Power Batteries in the Device Replacement Batteries department at Lowes.com