PMD Products Engine Cylinder Compression Tester Gauge Tool M14 M18 Auto Truck Car 2 Adapters 14MM 18MM for a wide number of vehicles (spark plug types/depths) Kit includes 1 rubber cones end for quick check (no need to thread into head) 3" Gauge has dual color scale with 0-300 PSI, 0-20 kPa Assembly: 13" long 14mm Flexible Rubber Hose with removable Schrader Valve Includes 14mm and 18mm spark plug adapters