Made from stamped .100" aluminum and powder coated black.  Attaches with 3M double sided foam.  Adds another layer of protection from scrapes or punctures.  Especially helpful where the boots rub the cases.  Sold in pairs.  The adhesive doesn't like to have gas spilled on it!   Although it is rare, we have heard of a few of these with the adhesive turning loose.  We recommend that you consider using some liquid adhesive on the double sided foam as well.