BatteryGuard(TM)Prolong the lifeof your battery. Maximize your battery's performace. Excessive shock and vibration are two of the leading causes for battery failure. Megaware BatteryGuard(TM) sits under your battery and absorbs the gravity shock caused by excessive vibration and up and down bounce.Features:Reduces up to 80% of the G-shock caused by excessive shock and vibrationProtect against premature battery failureFits up to Group 31 batteriesFits virtually any size batteryGreat for boats, automobiles, ATVs, Trailers or anywhere shock and vibration can damage a batteryCan easily be trimmed to custom shapes or sizesSave money by protecting your battery investment