Fusible Interfacing is a non-woven, polyester blend for sewing projects requiring stabilization of a fabric, reinforcement of a fabric or a bit of extra body to a material. It is mostly used while sewing garments such as shirt cuffs, collars and button holes, dresses, blouses, waistbands, and jackets, but is also used in home décor projects and handbag creation.All Therm O Web Fusible Interfacings are machine washable, dryable and dry cleanable. Iron-on Interfacings allow for construction of the garment without extra pinning! Adheres to the fabric in seconds! Use Light Weight for lighter fabrics such as: chiffon, light cotton, rayon, satin,silk, taffeta and sheer fabrics. Use Medium Weight for mid weight fabrics such as: medium cotton, light denim, flannel, fleece, linen and light wool. Use Heavy Weight for thicker fabrics such as: corduroy, heavy cotton, denim, tweed, velvet, and heavy wool. Use Fusible Fleece on most fabrics to add body and loft to a project.