The 5000 SP Series charges are the only Marine UL listed chargers available with a battery type selector switch, allowing you to charge lead acid (Flooded), GEL or AGM type batteries. They are tested by Marine UL for safety and durability against impact, vibration, temperature and shock.  Each has 3 stage charging, with temperature compensation, delivering the greatest charge when the battery is most able to accept it thereby preventing overcharging and extending the battery life.  Up to 3 battery banks can be simultaneously restored.   These chargers can also be used as a DC power supply to power such components directly as bilge pumps, lights, etc. without a battery in the system.