Ditch the heavy 1 lb clutched alternator pulley in favor of this billet aluminum version. It's designed using high tech CAD software and crafted on one of our CNC's to reduce the rotating mass and get every last hp out of your engine. Our version weighs 5 times less than the OEM pulley, and because its made on a CNC has a total runout of less than .001"! All this means a smoother and quiter engine that revs quicker off idle. Comes complete with high grade nut and thrust washer. Installs quick but please follow all Volkswagen installation instructions. This part fits all MK4 Golf, Jetta, GLI, New Beetle, and 337 1.8T and 2.0 engines, as well as all Audi TT MK1 1.8T 180hp and 225 hp.