About this item: [Wide Compatibility]--This battery isolators are small and suitable for almost anywhere, for ATV, UTV, Boats, RV's, marine vehicle, truck, caravan[Working Voltage]--Voltage Sensitive Relay (VSR) cuts in at 13.3 volts and cuts out at 12.8 volts to your primary battery is always and ready to run your vehicle[Function]--With the engine running the VSR will engage when the starting battery reaches 13.3 Volts and the LED light will illuminate. This means that both batteries are now linked and the system is working.Once you turn off your vehicle the system will disengage the two batteries as it reaches 12.8 Volts, leaving your main battery safe to start again[Important Note]--When connecting accessories to your second battery they are fused within 0.98FTProduct parameters: Type: 12V Voltage Sensitive RelayContinuous current: 80-100AInstantaneous current: 125ACurrent Consumption - Charging: 240mACurrent Consumption - Standby: 8mADetachment delay: 5-10 secondsRecommended Fuse: 80AmpPower stud: M6 copper screw nutSurge Protection: Built-in1. When the battery power is low, disconnect the auxiliary battery, and first the charging and operation of the main battery.2. After the main battery is fully , it will automatically charge the auxiliary battery without affecting the power supply of electrical equipment.3. Automatically cut off the connection of the main battery and the auxiliary battery when it is not charging, so there is no need to worry about the engine being unable to start due to lack of power.Material: ABScolour: blackPackage Contents: 1 x battery isolatorOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.