OTCs Truck Circuit Tester is designed for testing electrical circuits and locating shorts, grounds, and open circuits. For use on 12V - 24V systems. Versatile tester features a 7 inch long stainless steel probe and a red coiled cord that stays compact until you need more length then has the capability of stretching to a full 24 feet. The extra large clamp can be attached to larger nuts, bolts, and other grounds than a typical smaller clamp can. Value is at the core of the OTC tool and equipment portfolio. For a simple repair or the most complex drivability concern, these award-winning tools universally solve problems faster, and at better value, than any other product line available. Whether it's a specialty tool or unique piece of service equipment, OTC provides top solutions to modern automotive service challenges while increasing technicians' productivity and shop profits.