Originally intended to use with long-arms, the clamp is made from a mostly rigid, orange, heavy-duty plastic and it has an interesting flange on the side. You know what? You can hang things from that flange!
The plastic stretches to fit around most tables. The tips of each side of the clamp are not slick and to help keep them in place and to help protect the surface of your table.
I will probably use them to help hold quilt layers in place on my table when I baste but I think having just one in a class would be very handy to hang your trash bag from. Way better than a paper bag taped to the table!