Electrolyte Suspension system VMAX tanks utilize an electrolyte suspension system consisting AGM (Absorbed Glass Matt) of a high porosity that totally absorb and contain the electrolyte; No silica gels or any other contaminants are used Heavy Duty Grids: VMAX heavy duty lead tin alloys provide an extra margin of performance and service life in either float or cyclic applications, even after repeated over discharges Maintenance Free Operation: There is no need to check specific gravity of the electrolyte or add water to VMAX tanks during float service life; In fact, there is no provision for this type of maintenance The VMAX MR137-120 is not just a battery; it is a powerhouse engineered for the most demanding marine environments. As a Group 31 Deep Cycle AGM Battery, it delivers a perfect balance of high cranking power (900 MCA) and long-lasting energy storage. Whether you are navigating rough waters or powering an off-grid cabin, the VMAX electrolyte suspension system ensures your battery remains leak-proof and efficient. Unlike traditional lead-acid batteries that require constant maintenance, the MR137-120 is completely maintenance-free. Its "Tough Batteries for Tough Applications" philosophy means it thrives where others fail, offering an expected lifespan of 8-10 years in float service and up to 3,500+ cycles at 10% depth of discharge. Key Technical Specs: Nominal Voltage: 12V Capacity: 120Ah (20-hr rate) BCI Group Size: 31 Terminals: M8 Screw-in inserts (included) Dimensions: 12.9" L x 6.8" W x 8.7" H Weight: 75 lbs