I am power wheelchair bound and I can only travel to a store on the Paratransit bus that has a wheelchair lift. The bus limits the amount of packages that I can carry. I needed a large backpack to carry large amounts of groceries. I ordered the Monster Bag. I received it quickly. The size is ample and it is made of very durable material. The straps have a anti slip piece on each to keep it from slipping. My only suggestion is that it have a mesh sleeve that slips over the back of seat and is secured with headrest grommets like a smaller bag I have.