The Duffel is the latest addition to built's OverBuilt line. Made with the same “Strong-Rib” abrasion resistant fabric, fleece lining, and ultra thick Neoprene core - but bigger. The Duffel is made to take anything from textbooks to beach books. And their funky new custom hardware attaches a shoulder strap through a unique loop sewn right into the bag itself - and in combination with the elastic nature of neoprene it makes the whole bag act as a suspension system between you and your load.