The Black and Decker Battery Maintainer/Charger keeps your 6 Volt and 12 Volt batteries at optimal capacity with fully automatic, high frequency charging and reverse polarity protection. It's perfect for vehicles that only see seasonal use, including RVs, specialty vehicles, antique & classic cars, marine deep cycle batteries, motorcycles, ATVs, snowmobiles, personal watercraft and more. Keep it plugged in during the off-season, ensuring your batteries will stay topped off without ever being overcharged or damaged. It comes with two different connector sets, including battery clips and battery terminal rings. The BLACK + DECKER BM3B is also sealed for protection against moisture, dust and oil, so it's perfect for your garage, shop or shed.