Gain up to 5% of horsepower by installing this filterkit. It allows the oil to flow more freely, which reduces oil levels in the engine sump, thereby reducing oil/flywheel obstruction. The filter is re-usable making it the last oil filter you will ever purchase. It pre-cleans the oil by grabbing metal particles with three high power magnets. Then it filters the oil by utilizing a fine stainless steel woven mesh element to catch particles as small as 25 microns. A smart feature is the so-called pressure by-pass valve to prevent high oil pressure conditions caused by extremely cold weather or really dirty oil. We have three styles available chromed, polished or black anodized with highlighted polished accents. The filter is for use on Evolution and Twin Cam engines.