Alerion Express 20 framed winter cover. Our Alerion Express 20 framed winter cover is delivered with a 3/4 inch Galvanized Steel frame and is fabricated using a 13.5 ounce Boatshrunk canvas. The Alerion Express 20 winter cover is fabricated in a two piece construction. The cover also includes four vents, entryway door and secure tie-downs. Please inquire about our Alerion Express 20 winter cover.