guaranteed to fit singer sewing machine models:
1000, 1036, 1050, 1100, 1410, 1411, 1425, 2000, 2000a, 2001, 2010, 266, 290, 301, 401, 411, 431, 4552, 4562, 4610, 4622, 500, 501, 502, 503, 503a, 5910, 600, 603, 604, 610, 6233, 6234, 6235, 625, 626, 6267, 6268, 628, 629, 630, 631, 635, 635e3, 635e6, 635e7, 636, 638, 639, 640, 645, 646, 649, 6740, 6800, 6900, 700, 7028, 7033, 706, 708, 714, 717, 719, 720, 721, 724, 725, 729, 734, 737, 740, 746, 750, 755, 756, 758, 760, 766, 770, 774, 775, 776, 778, 784, 786, 8019, 900-3, 9005, 9008, 9010, 9012, 9015, 9018, 9020, 9022, 9027, 9032, 9123, 9133, 9135, 9137, 9143, 920-3, 9210, 9217, 9224, 9240, 9323, 9400, 9408, 9410, 9416, 9417, 9420, 9423, 9430, 9432, 9440, 9444