OTC 3633 Mini-coil Cord Circuit Tester Small handle with needlepoint stainless steel probe allows easy back probing and piercing Special threaded probe comes with screw on alligator clip for additional versatility Useful in testing electrical circuits and locating shorts grounds and open circuits Features 12 feet heavy-duty red coil cord lead and checks 6 and 12 volt systems Dwell measurement and O2 cross counts