Quickly and Accurately Check Compression on Gasoline Engines. Gauge registers 0 - 300 P.S.I. and 0 - 2100 kpa. Fits 14mm and 18mm thread sizes. 20100 Valve Core 20530 10mm Adapter-ORDER SEPERATLY 20540 12mm Adapter-ORDER SEPERATLY 20280 14mm Adapter 20380- Adapter for 5.4 Tritan Eng 2005-ORDER SEPERATLY *No replacement guage *Not for diesel * Hose approx 20 1/4" with adapter *Cannot use a standard valve stem core *Must use the 20100, works for both valves needed on the tool, If you use anything else the reading will be inaccurate *Won't work on Diesel