The main function of this product is to switch on, it can be used alone, it can be also connected to control to use, but this product does not include additional control relay, and if the controller is connected, it mainly used in the dual battery. Features: The surface is made of fine quality nylon material, stable structure and long service time. Built in pure copper coil, with strong conductivity. With a fixed frame, which is stable on working. Silver contact material, arc extinguishing resistance, low contact resistance and convenient installation. Help extend battery service time. Specifications: Rated power: 12Volt, 24Volt (optional) Rated current: 500A Coil power: 7.2W Color: black Material: metal Package size: 90 * 82 * 60mm / 3.5 * 3.2 * 2.4in Package weight: 257g / 9.1ounce Packing List: 1 * Relay