These are new old stock from various manufactures, for machine embroidery thread. Sulky, FuFus, Airplane, August Industries. Most are Rayon and a few say Poly The yards for each size will vary within the below listed yards. Some of the colors have multiple size choices available, see below for size chart. These are factory sealed and labeled and the total yards will fall within the specified range, which has been determined by weight. Size Yards A 4100-5468 B 2734-4100 C 1367-2734