.1) 7.5” diameter, wood covered with white taffeta ribbon on inner ring and gray grosgrain ribbon on outer ring. 2) 6.25” diameter, black plastic (?) with lengthwise grooves on contact surface of inner ring. This has marks that suggest the material might be whalebone although I can’t imagine using whalebone for this purpose, and that there would not be a visible join. 3) 5.75” diameter, wood covered with torn strips of unbleached muslin.