Made from copper plated zinc alloy, this 12V battery isolator switch has a handy rotary on / off knob for ease of use. It provides quick battery disconnection for security & storage & fits all 12V negative battery posts on cars, caravans, vans & motor homes. DURABLE: This 12V battery isolator switch is made from copper plated zinc alloy ROTARY ON/OFF KNOB: It has a handy rotary on / off knob for ease of use QUICK BATTERY DISCONNECTION: The isolator switch provides quick battery disconnection for security & storage FITS 12V BATTERIES: It is designed to fit all 12V negative battery posts on cars, caravans, vans & motor homes