Hog rings are basically C shaped & D shaped with sharp or blunt points. They are bent into a circular or triangle formation by the hog ring plier in order to fasten two objects together. Thanks for its easy operation, hog rings are broadly used in installation or repair of fencing, wire cages, razor wire, barbed wire, car upholstery, trellis, gardening, rebars and so on. Hog Ring Styles. Galvanized, copper plated, aluminum and stainless wire are basic material for producing hog rings.