Singer models 600, 603, 604, 620, 625, 626, 628, 629, 630, 635, 636, 638, 639, 640, 645, 646, 648, 649, 737, 750, 758, 755, 756, 770, 775, 778, 1000G,1040G, 1060, 1411N, 1411U, 1425N, 1425U Outside diameter: 27.4mm Height: 7.1mm Axis diameter 2.2mm