An oil catch tank is used in turbo applications, or high-performance racing applications where excessive blow-by (leakage past the piston rings) of air and vapor occurs. This creates a positive pressure in the crankcase. During engine operation, blow-by gases, as well as oil mist from the rotating components of the engine,pass through the PCV valve and are routed back into the intake for the engine to burn off. However, some of the oil mist and other by-products settle along the engine intake and over time form a gunk. The oil catch tank collects such oil mist and condenses the vapors while allowing cleaner gases to be passed back into the intake. Features: Universal fitments, can fit on most cars. better mileage, better performance and preserve engine life. Built-in air filter included Professional installer is highly recommended. Fitment: FOR N54 335 FOR 2006-2011 E90 Sedan 335i / 335xi FOR 2006-2011 E91 Touring 335i / 335xi FOR 2006-2012 E92 Coupe 335i / 335xi / 335is FOR 2007-2012 E93 Convertible 335i / 335xi FOR 2008-2010 E60 Sedan 535i / 535xi Color:Black Material:Aluminum Alloy Package Contents: 1 * tank Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.