cotton covered poly boning 1/2" polypropylene ~ black (12 yards) item4ever it offer high fashion support for nursing cover, caps, toy, gift designers, strapless dresses, bathing suits, arts, crafts, bra, wedding veil, etc. . polypropylene sew/woven inside and is flexible, durable, yet unbreakable. dry cleaned and washable. easy to sew by hand or machine, can be used directly by sewing garment edges, not require additional fabric to cover. clean finished. light weight and comfortable to wear.