Mighty Max Battery 6V 4.5AH Replaces SLA640 APS46 LA640 SLA4-6 Rechargeable Sealed Lead Acid 645 Backup Power Batteries in the Device Replacement Batteries department at Lowes.com
Dual Lite BDG SLA4-6 Battery - Replacement UB645 Universal Sealed Lead – Infinisia
Agt Battery LA640 SLA4-6 Battery Replacement - UB645 Universal Sealed Lead Acid Battery (6V, 4.5Ah, 4500mAh, F1 Terminal, AGM, SLA) - Includes TWO F1 to F2 Terminal Adapters - Walmart.com
MIGHTY MAX BATTERY ML4-6 - 6V 4.5AH Replaces SLA640 APS46 LA640 SLA4-6 SLA Battery MAX3422068 - The Home Depot