These are just like the drawstrings that I put into the shorts, pants and skirts that I make. I have had requests to purchase these separately, so I decided to go ahead and put these up as a separate item on my site. They are just strips of the same Texas grown organic cotton jersey fabric that I sew with. A lightweight, stretchy, tee shirt fabric. The strips are about .75" wide  68" long. Available in natural and black. The strips are flat, but when stretched will roll in on itself because the fabric is cut along the length of the fabric, so that it will roll lengthwise. Then you can knot the ends, as shown. See more images below.