IJO1965 Features: * Spark plug tester * Quickly checks Spark at plug wire * Handy tool to check ignition spark without removing the spark plug * Tool is specially calibrated to measure ignition voltage * Works on both standard and electronic ignition systems * Easy to use * Simply adjust calibration screw to proper gap size * Attach spark plug wire to end of tester * Clamp tester on engine to ground * Crank engine and check for spark Dimensions: * Weight: 2 oz