I have the floor Q Snap frame. The clamps are half pvc pipes with ridges on the inside. They grip the quilt and you can turn and tightened or loosen the tension easy. You can buy the pvc long clamps at Q Snap website.
http://www.qsnap.com/default.asp I would call and ask about the diameter of the pvc before ordering. I think the Q snap frame are not standard size PVC.