This Saratoga Bag is a perfect accessory to the Postal Mail Cart. Two bags will fit on one cart. The top flap of the bag fits loosely and covers 6-1/2" of the front of the bag to keep mail dry. The bag is constructed of 18 ounce 100% cotton canvas. The canvas is water and mildew treated. The Saratoga Bags feature a 1-1/4" heavy-duty welded steel wire D-rings and two adjustable back pack buckles for closing.