The fully automatic Battery Tender® 4 AMP is a top-of-the-line 12V or 6V switchable battery charger, perfect for automotive, motorcycle and marine repair and maintenance shops. With 3x the power of the Battery Tender® plus this charger is versatile and powerful. Equipped with a simplified 4-Step Automatic charge process. All Battery Tender® chargers automatically switch from full charge to float charge mode. Reverse hook-up protection makes connecting your charger safe and easy to do. LED light indicators make selecting your charge mode simple.