Description
Handheld Professional Autos Exhaust Back Pressure Tester System Diagnostic Tool Exhaust System Diagnostic Tool Exhaust Back Pressure Tester Adaptor fits into oxygen sensor hole enabling back pressure of mufflers and catalytic converters Gauge adapter threads into oxygen sensor ports (both 12mm and 18mm). Test at idle and at2500 rpm's. Pressure should be below 1.25psi at idle and below 3psi at 2500rpms. Higher readings indicate a restriction which should be corrected.