These heavy-duty NOMAD USA canvas bags are made of duck cotton which is made more secure and top quality with reinforced Vinyl backing. The added strength to the bag is given by reinforcing it at all its stress points. This strong and super strength bag can hold a lot of weight and material without snapping. The big pockets provide you enough storage that you can easily carry all your valuables safe and sound. The drawstring closure and flap cover closure with double straps that are super strong and sturdy. This makes the bag safe and protected.