This simple device is quickly and easily fitted to the battery of any vehicle, with either round or flat battery terminals. Once fitted, a turn of the knob disconnects the battery from the electrical system. For further security the knob can be unscrewed and removed disconnecting the battery completely. A fused bypass is included so that power is still provided for alarms, clocks, etc., but the fuse will blow immediately if an attempt is made to start the car without first replacing or tightening the knob. Read \" How-To Maintain Car Battery Life \" from Technical Articles for some useful tips to keep your car battery stays healthy.