Includes compression gauge, O-ring, compression gauge and instructional pamphlet|Flexible hose and quick-disconnect coupler permit fast, easy engagement of threaded fitting into spark plug hole|Gauge has convenient side release valve and dual reading scale for both PSI and metric values (0 to 300 PSI, 0 to 20 kg/cm²)|Equipped with neoprene -inO-in rings for positive finger-tight seal|Includes adapters for regular 18mm spark plugs and for regular and long 14mm spark plugs