This Aux Belt Idler Pulley is designed to fit various BMW models including the X3 E83 2.0D and 3.0D from 2004 to 2011, the 5 Series E60, E61 2.5D and 3.0D from 2004 to 2010, the 3 Series E46 2.0D and 3.0D, and the 7 Series E65 4.4D from 2005 to 2008. It functions as a guide or deflection pulley for the v-ribbed belt system. The pulley has a width of 43 mm, an outer diameter of 70 mm, and weighs 0.292 kg. It comes with a screw and is made of metal. This part is manufactured by Febi, with the part number 24639. Please ensure compatibility with your vehicle using the make and model tool or by contacting us before purchase. The product is intended for use as originally designed and should be installed by a competent individual. Fitting instructions are usually not included.