Singer models 66 class, 99, 185, 201, 240 and 250 series, 288, 327, 328, 329, 337, 338, 347, 348, 348,350 360 series, 401, 403, 404, 413, 416, 417, 418, 457, 466, 476, 477, 478, 500, 502, 503, 507,509, 513, 514, 518, 522, 527, 533, 534, 538, 560, school models 714, 717, 719, 724, 774, 776 with apollo type hook Outside diameter: 20.5mm Height: 10.8mm Axis diamter 6.2mm Alternative number 32522