This is a stiff ribbed ribbon, used to reinforce e.g. waistbands, bind corset edges or hat brims, or even as a foundation for neck ruff. Named after Lord Petersham, a military officer in the 19th century. Petersham is often confused with grosgrain ribbon but the important difference is that the petersham has a scalloped edge which allows you to shape the ribbon. Usually made out of 100% Rayon.