"Battery Tender DVS - 40 Heavy - Duty Fast Chargers... top - quality battery boosters. Click image to enlarge... These portable Chargers have been servicing the marine industry for years, and are ready to power up and maintain your boat battery's strength. Employ a maximum power output of 600 watts out of your TWO 12-volt outputs with a 40 amp current. Features a variety of software configurations to suit your needs: DELCO, standard, seals, VRLA, GRT, AGM and GEL. You'll appreciate the status indicator lights that keep you abreast of the charging status: Solid Green means the charger is ready to begin charging the battery; Solid Red means your battery is charging normally; Flashing Red means the charger is experiencing an abnormal condition and Flashing Green means the charge is complete. All Chargers come with jumper cable-type harnesses with heavy-duty alligator clamps. Has short-circuit and reverse polarity protection for your safety. Choose between a Single-Sealed AGM and Standard Charger. The rundown: Dua"