The Battery Tender Plus Battery Charger is much more than a trickle charger. Powered by BTP microprocessor technology, it has a 'brain'. Utilizing a 4-step charging program (initialization, bulk charge, absorption mode and float mode), it allows you to simply connect the charger to a battery, either in or out of a vehicle, and forget about it until you are ready to put the battery to work. Like all Battery Tender chargers, at the end of the regular charger cycle it automatically switches its output voltage to a safe, storage or float level that eliminates the need to worry about the damaging effects of overcharging, and the resulting need to check on the condition of the battery. If or when the battery voltage drops too far under load, output power resumes and the charging cycle begins again. The unit also features sparkproof connectors, short circuit and reverse polarity protection, an easy to understand charging status LED indicator, a quick connect harness for use in hard to reach areas and almost no current draw from batteries connected to it. Choose the Battery Tender Plus that's designed especially for your battery size/type. Battery Tender Plus 12-Volt - for 12-volt lead-acid batteries Battery Tender Plus 6-Volt - for 6-volt lead-acid batteries Battery Tender Plus True Gel Cell - for use with True Gel Cell batteries, as well as 12-volt lead-acid batteries. Solid state two color LED indicates stage of charger; a quick connect harness for use in hard to reach areas Complete 4-step charging program (Initialization, Bulk Charge, Float Mode) allows for optimization of battery power, without overcharging Almost no current draw from batteries connected to it Set includes: Battery Tender Plus Brand: Deltran Model: 021-0128 Materials: Stainless steel, plastic Color: Black Dimensions: 10.50x3.50x10.50 Weight: 2.3 Color: Black.