The Black & Decker BM3B battery charger/maintainer features 6 volt and 12 volt charging selectivity. Use for battery maintenance, charging RVs, specialty vehicles, antique and classic cars, marine deep cycle batteries, motorcycles, lawn mowers, ATVs, snowmobiles, personal watercraft and more. Maintains battery charge in stored vehicles and battery applications. Includes three connector sets: DC accessory plug, battery clips, and battery ring terminals. Fully automatic, provides a charge when needed, stops charging when battery is fully-charged or topped-off. Built-in circuit protection guards against overcharging, reverse polarity or short circuit.