Screws Down to Sewing Machine Bed in 2 Threaded Holes to Right of Needle Plate, This binder is for light to medium weight apparel, quilting, binding and tapes, not for thicker fabrics such as upholstery which will not feed through the mouth of the binder.

Swing Away Binders allow reverse stitch back tacking. Stationary binders only allow forward feeding. You can tack in place without any stitch length, but reversing with stitch length would bunch up the fabric against the stationary binder.
Specifications