The 15/16" Outside Diameter Pop Rivet, Disk Glide is attached to the chair leg with a pop rivet. These Pop Rivet, Disk Glide are made of metal with a rubber base. The pop rivet holds the glide firmly in place. To remove just use a ¼” drill bit and drill the head off the old rivet. To install you will need to use a pop rivet gun. These can be found at any home improvement store.