PMD Products Compression Gauge Test Set for Engine Cylinders Diagnostic Tester 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 Fittings: M10, M12, M14, M18 (Male, With O Ring) Includes 14mm and 18mm spark plug adapters