When you take your hitch off your receiver and put it in the back seat of your car or truck, you are putting snow, dirt, rust and whatever else you picked up on your nice clean floor. I had the girls make bags to hold my different sized receivers to keep the road crud off my shiny new floor mats. These bags come in two sizes; 9" x 18" and 11" x 18". The materiel is the same heavy duty cloth we use for our trolling Buggy Bags and Beefy Bags. The bags have heavy YKK zippers and two handles for years of hard use.