Stalwart 75-1100 Hawk 4-pc Electrical Circuit and Voltage Testing Kit Instantly tells whether or not spark plugs are firing Quickly find dead spark plugs 6 and 12 volt auto circuit tester Checks complete accessory circuits For use on Marine, Auto and Trailer For 110 Volts and 220 Volts. Instantly tests Fuses, Outlets, Extension cords, Switches, Ect.