Brass Green battery switch made of heavy duty Brass alloy,Durable zinc alloy terminal.Heavy Duty,Suitable for most batteries, under the condition of 12V voltage, continuous current 125A, instantaneous current 500A,Designed for high-current applications.loose is power off, tightening can be conductive.Battery operated switch to engage power just hand tighten the green knob,Slightly loosen the green knob to disconnect all power(power off only need to turn the switch (green) loose 2-3 laps on the whole vehicle power off, power on the switch properly tightened, you can start the vehicle)Used for Car, Vehicle, RV and Boat batteries which have a standard 15-17 mm cone top post terminal, also used for electrical equipment.Purpose: used for battery to isolate and secure the electrical system, eliminate any power draw from the battery when vehicle or boat is not in use, disconnects the battery safely.