VMAX MR137-120 12 Volt 120Ah Group 31 Deep Cycle Marine Battery. Heavy duty AGM battery made with special plates and top of the line plate separators giving these batteries superior performance and unmatched deep cycle capabilities. AGM Electrolyte Suspension System. Custom Built Military Grade Alloys. Fast Charge Delivery Capabilities. Extremely Low Self Discharge Rate. Safe to use in small areas; no spills, no toxic fumes. Extreme Vibrations, Heat and Weather resistant. Sealed Non-Spillable