These are the cardboard cores from spools of industrial woolly sewing thread. They can be used as is for separating thread. You can also get creative and use them for crafts. One nursery school apparently used them to make Christmas trees. They were actually in use until recently, so there may be some minor soiling. They are cone-shaped, 17.5 cm tall. The top diameter is 3 cm and the bottom diameter is 5 cm. Thank you for looking.