Schumacher SE50 Electric Battery Charger 2/10/50-Amp 12V (Certified Refurbished) This Certified Refurbished product is tested and certified to look and work like new. The refurbishing process includes functionality testing, basic cleaning, inspection, and repackaging. The product ships with all relevant accessories, a minimum 90-day warranty, and may arrive in a generic box. Only select sellers who maintain a high performance bar may offer Certified Refurbished products on Amazon.com Microprocessor controlled  automatically adjusts the amperage rate to charge & maintain. Multi-stage charging for added precision, safety and battery life Charges 12 volt Standard, AGM and Deep-cycle batteries Reverse hook-up protection  Charger will not operate if clamps are reversed.