Trailer Hitch Receivers and Receiver tube adapters and trailer hitch receiver extentions allow you to use the same ball mount in different size vehicles when needed. Receiver adapters or receiver extenders are perfect for bike carriers, cargo boxes, cargo carriers, rear cargo baskets and more. The hitch extender will extend the reciever opening 6"-18" further from the vehicle. Keep in mind this also reduces the tow rating by 50%. Great way to get a cargo basket or a bike rack far enough away from the car to accomodate gaining entry with out removing the hitch mounted bike rack.