K-TUNED Valve Cover Breather Filter. Use this valve cover breather filter to keep warm, oil saturated crankcase vapours from re-entering your engine through the intake pipe. Allowing crankcase vapour to re-enter the engine hurts performance and leaves a nasty oily residue all over the inside surface of the intake manifold. To prevent this, you can delete the factory valve cover vent hose and replace it with our breather filter. Sold individually with a clamp to hold it in place. Suitable for all K-series engines.