This petersham grosgrain uses a soft and stretchy recycled polyester yarn that gives this ribbon a slight amount of stretch.  The stretch provides enough movement to allow it to be applied to the band, brim or sweatband of a hat and fit snugly.  Also this works great when top applied over seams of stretch fabrics.  Also available in a foldover version, Recycled Polyester Soft Stretch Grosgrain Binder can be found here.