All metal construction. pair of 1 inch rifle or shotgun sling swivels to attach to swivel studs for two point sling. No studs are included. Accepts 1 inch wide slings. Sold in pairs. Steel construction with black finish. These are the same swivels that we sell when we include them with our handmade leather rifle slings and the same ones that we use with our own personal firearms. The nut is free spinning, which means that when the nut is tightened to close it, the nut will spin freely until positively engaged. In other words, the nut is not supposed to tighten down. That is an intentional product design to help prevent accidental opening.