French Fuse is a Woven Medium / Heavy interfacing with one fusible (glue) side and one soft side. This lightweight fabric is very useful to reinforce garment facings, and thin, delicate or stretchy fabrics. Interfacing Weight " Pre-Shrinking All interfacings should be preshrunk. Sew-ins can be preshrunk through a press steaming process. Fusible can be preshrunk by immersing in a bowl of very hot (not boiling) water and allowing to sit until the water cools to room temperature. Gently squeeze, then roll in a towel to remove excess moisture and allow to air dry. Press with a medium heat, dry iron. Test the heat of your iron in one corner first. If the fabric begins to shrink up on itself, lower the heat of your iron to another setting and try again. Machine wash as needed in warm water only after fusing.