Quickly detect electrical voltage intensity, power, ground, and circuit integrity for each spark plug with the ABN Automotive Circuit Continuity Tester 6-48V DC Test Pen, LED Digital Display. This tester checks voltage/voltage drop without the use of a multimeter. It instantly detects broken plug wire and carbon clogged plugs on 6-48V DC systems in cars, boats, trailers, vans, RVs, motorcycles, airplanes, and snowmobiles with a voltage measurement from 4V to 60V. The digital display reads the accurate voltage value so you do not have to guess, and the LED lights indicate power (red) and ground (green). The needle-sharp stainless-steel testing probe allows for easy piercing. This tool has an 8-inch length for easy use in confined areas and the spring cable extends 12 feet to take anywhere. Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.