Sealey-VSE953-Catalytic-Converter-Back-Pressure-Test-Kit-Sealey-VSE953-p-Used-to-establish-the-working-condition-of-the-catalytic-converter-&-silencer-by-measuring-the-relative-back-pressure-of-the-system-Simply-connect-into-the-exhaust-system-using-either-of-the-two-oxygen-sensor-dummy-adaptors-supplied-in-the-kit-Gauge-features-a-colour-coded-scale-for-easy-diagnosis-&-reads-both-pressure-&-vacuum-so-can-be-used-on-other-areas-of-the-vehicle-allowing-testing-of-low-pressure-fuel-sy