Bosal Craf-Tex Double Sided Fusible Plus adds structure to the Leave the Light On Pattern. Each pack includes four sides, four windows, and six roofs. Apply your fabric to either side of the Bosal then, using a press cloth, iron your fabric and the interfacing with now adhere to the material and you are ready to start sewing. Bosal's Craf-Tex Double Sided Fusible Plus is made using 100% polyester and is machine washable. Made in the USA.