Odyssey Extreme Duty 31 Series AGM (Absorbent Glass Mat) Battery. Longer Service Life (3-6 Years) with 3 yr Replacement Warranty. 70 Percent Longer Cycle Life (Up To 400 Cycles at 80 Percent Discharge). Faster Recharging (Reserve Capacity of 205 min at 25 AMPS). Maintenance Free – NO LIQUID. 78 lbs per Battery.