Place the new upholstery on the seat base and start the installation by using a few new retaining rings in the corners. Work your way around, placing a new ring every couple of inches and checking your work to ensure the upholstery is being installed straight and firmly so there are no wrinkles. Once you have the seat base retained, pull down the upholstery around the foam and secure it to the frame. There are more listing wires that go into the end of the upholstery here as well, so don't forget them. We already had a stash of retaining rings (also called pig or hog rings) and installation pliers, but Mustangs Plus carries these as well.