This ribbon is the ribbon the Nu-kote ribbon was fashioned after. This is the original Olivetti ribbon. This ribbon works with numerous Montgomery Ward, Olivetti, Sears, Tower and Underwood typewriters.
Montgomery Ward Escort 33, Escort 44, Escort 55, Escort 66, Olivetti 203, 230, 240, 245, 250, 270 Typewriters, A730, A770, Audit 7, Audit Series 302, Series 502, Series 513, Series 722, Series 723, Series 725, Series 731, Series 732, Series 733, Series 930, Series 1502, Series 1505, Series 1506, Series 1512, Series 1513, Series 1722, Series 1723, Series 1731, Series 1732, Series 1930 Calculators, Autotronic 730 Calculators, College Calculator, Olivetti Dora, Editor 2F-Fabric, Editor 3F-Fabric, Editor 4-Fabric, Editor 5-Fabric Typewriters, GR.4, Graphika, Hispano-Olivetti Lexicon 80, Hispano-Olivetti M40, Hispano-Olivetti Pluma 22, Hispano-Olivetti Studio 44, Hispano-Olivetti Studio 46, Lettera 21, Lettera 22, Lettera 25, Lettera 31, Lettera 32, Lettera 35, Lettera 35i, Lettera 35l, Lettera 36, Lettera 36C, Lettera 37, Lettera 82, Lettera S14, Linea 88, Linea 98, Typewriters, Logos 25, Logos 240, Logos 245, Logos 250, Logos 270, Logos 600 Series, Mercator 5000, Mercator 5102, Mercator 5103, Mercator 5105, Mercator 5106, P 602, P 603, P 652 Calculators, Praxis 48 Typewriter, Roma Calculator, Scribe, Standard, Studio 42, Studio 44, Studio 45, Studio 46 Typewriters, SV40, TE300 Printers, Tekne 3, Tropical Portable, Valentine Typewriters, Sears 52010, 52020, 52030, 52032, 52040, 52042, 52050, 52211, 52910, 52912, 52914, 52920, 52921, 52922, 52924, 52930, 52931, 52932, 52933, 52940, 52941, 52942, 52943, 52950, 52951, 52952, 52953, 52954, 52955, 52960, 52961, 52962, 52963, 52964, 52965, 52970, 52971, 52972, 52973, 52980-405, 52981-405, 52982, 52983, 52984, 52985, 52990-405, 52991-405, 52992, 52993, 52994, 52995, 405.52030, 405.52032, 405.52040, 405.52042, 405.52211, 405.52910, 405.52912, 405.52914, 405.52920, 405.52921, 405.52922, 405.52924, 405.52930, 405.52931, 405.52932, 405.52933, 405.52940, 405.52941, 405.52942, 405.52943, 405.52950, 405.52951, 405.52951, 405.52952, 405.52953, 405.52954, 405.52955, 405.52960, 405.52961, 405.52962, 405.52963, 405.52964, 405.52965, 405.52970, 405.52971, 405.52972, 405.52973, 405.52980, 405.52981, 405.52982, 405.52983, 405.52984, 405.52985, 405.52990, 405.52991, 405.52992, 405.52993, 405.52994, 405.52995, 603.52020, 603.52030, 603.52040, 603.52050 Typewriters, Tower Capri, Centurion, Chieftain, Courier Typewriters, Underwood 21, 250, 310, 315, 319, 320, 478 Typewriters and probably others.
These spools have a center hole big enough for the nut to screw onto the post.