THERM O WEB-Stitch n Sew Sew-In Interfacing. Specialty woven hair canvas interfacing is known for adding strength and stability with minimal stretch to fabrics. Use it for all kinds of tailoring and couture garment construction. This package contains one 25 yard bolt of 23 inch wide natural hair canvas woven sew-in interfacing. Made of 34% cotton; 31% viscose; 25% hair; 7% wool; and 3% polyester. Machine Washable. Made in USA.