Give your 2015-2020 BMW M3/M4 the protection it deserves with the Mishimoto Direct Fit Catch Can Kit. The introduction of the S55 into the M3 and M4 in 2015 was the first that the compact M's saw turbos from the factory, but these engines brought along another long-standing tradition - Blow-by.The Mishimoto BMW M3/M4 catch can kit uses proven engineering from the patent pending Mishimoto 2-Port Compact Baffled Oil Catch Can, with its 50-micron bronze filter and internal baffle to better separate the oil from the crankcase vapors. The engineers at Mishimoto designed a CNC-machined lid that features large inlet and outlet ports in order to match the inner dimension of the CCV hose. This baffled oil catch can defends your intercooler, intake system, and VANOS system from oil blow-by and helps maintain proper octane levels to reduce potential detonation.The kit comes with two direct-fit hoses, which require no modification to the engine cover, and one direct-fit billet aluminum mounting bracket that is extremely easy to install and mounts the can in a serviceable location! Two aluminum, 3/4" barb fittings connect the hoses to the can. And, like every Mishimoto oil catch can, this baffled catch can kit comes with the Mishimoto Lifetime Warranty! Our catch cans are different from most air-oil-separator (AOS) systems on a few levels. First, our catch cans are not heated. This means that all of the blow-by is able to condense in the can, including low-octane oil vapors and contaminated fuel vapors. Most AOS systems also drain the blow-by back into the oil pan, while our catch cans trap the blow-by and keep it out of the engine permanently. If you've seen what we've seen in the bottom of our catch cans, you won't want that draining back into your oil either.