New replacement top arm shaft washer.

Plastic, snap in place in just a few seconds. Removal of main shaft no longer needed.

Part # 163990-SN 

Fits Singer models: 533 Stylist, 534, 538, 600, 600E Touch-N-Sew, 603, 604, 620, 625, 629, 630, 635, 636, 638, 639, 640E, 645, 646, 648E3, 649, 750, 755, 758