polypropylene Open Top closure CONVENIENT: Folds up flat for easy storage with foldable reinforced bottom for extra durability. Rigid bottom keeps the bags flat and sturdy in your trunk so nothing will slide around in your car. Stays open and upright for easy loading. MULTI-USE: Ideal for groceries, general shopping, going to the beach, picnics, boating, concert events, laundry, storage and more. EASY TO CARRY: Our box bags have short side handles in addition to the shoulder straps making it easier to carry a heavy load. EXTRA LARGE CAPACITY: Bag Size: 16”W x 12”W x 10”D. Each of these box bags can hold as much a 3 plastic bag DURABLE: Made of heavy duty laminated, 100 gram Woven Polypropylene and recycled cardboard walls giving these bags a rigid structure when opened. Shoppers and checkers alike love these bags because they stay open and upright when loading.