The thrust washer fits over the idler wheel axle and provides a smooth gliding surface for the idler wheel. In many cases the original washer splits creating an uneven surface for the wheel when spinning. This is a new, unused original Dual part. It may come in either pink or clear (Dual produced the part in both colors and is part number 200-110).
Installation is simple. Just remove the idler wheel and replace the damaged washer with a new one.