Rubber washer for retaining the ball bearings in the single/multi tonearm position switch on the Dual 1219, 1229, 1229Q, and 1249 turntable models.
This critical part deteriorates with age (hardens, cracks apart) leaving the crucial tonearm position switch shaft with ball bearings exposed. A damaged washer can contribute to the breaking of the tonearm's outer dearing ring. And a worn rubber washer can alter the vertical position of the tonearm impacting tracking, cause skipping, and the automatic start function failure. When servicing one of the above models replacing this part is nearly always necessary.