Power Probe Blue T Tester includes the following features and benefits: a 20 feet jumper lead set; a bad ground indicator and short circuit indicator; a continuity tester and a relay and component tester. It has a built in flashlight that is easy to read backlit Voltmeter that allows one to read the voltage at the tip. It helps in eliminating wasted time running to the toolbox for a voltmeter. It has standard 4 millimeter jacks that ensures full compatibility with the gold series lead set as well as all other 4 millimeter leads, plugs and jacks already in the tool box. The rocker switch should be pressed forward and there will be a hot lead for powering up electrical components like cooling fans and relays. If the switch is pressed rearward there will be instant ground lead. The polarity tester instantly identifies positive, negative and open circuits. The continuity of switches, relays and diodes can be instantly checked.