For gasoline engine compression testing on domestic and foreign cars and trucks Screw-in adapters with O-rings provide professional accuracy Adapters included: 14mm and 18mm short solid, 14mm and18mm long flex and 14mm long reach Long flex 12" hose and adapters eliminate having to remove engine accessories to test compression Side release valve allows quick re-testing of cylinder without removing adapter 2-1/2" gauge has dual scale dial with ranges from 0-300 psi and 0-21 BAR