Radium Engineering Catch Can Kit, PVC 2017-2021 Honda Civic Type R (FK8) / 2023+ Honda Civic Type-R FL5This catch can runs inline with the PCV (positive crankcase ventilation) valve and retains it's factory function. When the intake manifold pressure is close to or greater than atmospheric pressure, the PCV "check" valve closes and, thus, this hose experiences no flow. Conversely, the PCV hose will experience "metered" vacuum when the engine is idling, steady state cruising, and decelerating. This would normally draw unwanted crankcase vapor, unspent