Check valves and rings, inspect for carbon buildup and late timing. * Adapters for a wide number of vehicles (spark plug types/depths) * Kit includes 2 rubber cones ends for quick check (no need to thread into head) * 3 inch Gauge has dual color scale with 0-300 PSI, 0-20 kPa * Gauge will hold pressure values and has quick push button release valve * Fittings: M10, M12, M14, M18 (Male, With “O” Ring) * Includes 14mm and 18mm spark plug adapters * Includes use manual with technical support Comes with 1/2" diameter x 14" extension hose, straight and angled fittings, rubberized gauge protector and a blow mold case.