The ProMar Recreational Marine Single Bank Battery Charger with Fully Automatic Charging charges, conditions and maintains batteries with a built-in safe maintenance mode. Single Present Charging Profile: Use with Lead Acid (flooded) or GEL batteries. Expanded LED Status Center: At-a-glance AC power, charging and ready/maintain LED indicators. Distributed On-Demand Technology: Automatically charges & maintains your engine crank battery while distributing all remaining charging amps to trolling motor batterie(s). Built-in Quality & Safety: 100% epoxy filled - Completely waterproof & shockproof. Dual in line DC safety fuses (multi-bank models), reverse polarity, ignition and temperature protection. Pre-Wired for Easy Installation, Max Batteries: 1, Ideal Use: Single 12V engine crank battery or Single 12V trolling motor battery.