These are old frames that are attached t short wooden cross bars using clamps into a long rectangle. The quilt sandwich is basted to the fabric, then it is rolled onto the long wooden bars, much like a long arm quilting frame. The frame is set onto backs of chairs or wooden "horses" for support while quilting. Frequently, the entire unit was attached to pulleys and pulled to the ceiling for out-of-the-way storage until the next quilting session. Women sat along each long edge and quilted. $15 is a good price for something like this, if you have a large ceiling for storage and want to hand quilt. Personally, I'd use a 14-inch hoop and sit on a comfortable couch.
SandyQuilter