This stainless steel spacer has been on every VW mechanics want list for years. Many Bosch alternators have been junked due to non-availability of this part. If you have an alternator that keeps destroying pulleys, you probably need this item. Works on Bosch , Motorola , and Chinese copies of Bosch alternators. If your bad spacer does not slip off the shaft easily, dis-assembly of the unit may be required for installation. Made in USA!