I recently purchased TrueGrips non-slip adhesive rings from a local quilt shop. They are made by The Grace Company.
www.graceframe.com. They are clear and a little larger than a dime. There is a very small circle cut in the center making it so that there are 15 small ones and 15 large ones in the package. I have not used them yet but thought I would pass along the information. I did see a demo at the quilt shop. They seem to work well.