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. On computer controlled vehicles from 1982 to present, use the Computer Memory Saver (25036) or Fuse Link (25049) to preserve the computer's settings when the battery is disconnected. The Fuse Link will allow enough currect through to maintain computer, radio settings etc. but will not allow car to be started.