Duracell Ultra 6V 12AH General Purpose AGM SLA Battery with F1 Terminals - SLAA6-12F at Batteries Plus
TORK 436 Battery Replacement - UB6120 Universal Sealed Lead Acid Battery (6V, 12Ah, 12000mAh, F1 Terminal, AGM, SLA) - Includes TWO F1 to F2 Terminal Adapters - Walmart.com