Product Overview Adapters for a wide number of vehicles (spark plug types/depths) Includes 2 rubber cones ends for quick check (no need to thread into head) 3" Gauge has dual color scale with 0-300 PSI, 0-20 kPa Fittings: M10, M12, M14, M18 (Male, With "O" Ring) Includes 14mm and 18mm spark plug adapters Compression Gauge Test Set for Engine Cylinders Diagnostic Tester 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" 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.