Features: 1When the engine is started, the starter battery and the supercharger battery are separated, and only the starter battery is allowed to be charged. When the charging voltage reaches 13.3 volts, the voltage?sensitive relay will be activated so that the starter battery and auxiliary battery can be charged. The red light in the upper left corner of the lighting indicates this situation. 2When the engine stops and the battery voltage drops below 12.8V, disconnect the VSR by separating the starter battery and the auxiliary battery. At this time, the indicator light will go out and the auxiliary battery will continue to supply power to all accessories without worrying about draining the starter battery. 3Compared with the battery isolation diode (0.6V), the voltage does not drop. When the motor is turned on, the storage mode allows no power consumption. 4Sturdy fiberglass reinforced nylon shell, high strength, corrosion resistant, not easy to be damaged, which has long service life. 5Support panel or surface installation, flexible to use, it can meet your different installation needs, bring much convenience for you. Package included: 1 x Battery Isolator 1 x Terminal 4 x Screws 1 x Manual