Simple to install and easy to operate, this shut-off switch ensures that everything is disconnected. Attach the switch to either the positive or negative terminal of your battery and the cable to the switch. Then unscrew the knob and take it with you to disable your car and discourage thieves. Great for cars in storage. The optional Fuse Link (25049) will allow enough power to maintain computer, radio settings etc., but not allow the car to start.