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.