I recently bought this for my 24ft trailer to fit a 4" rear bumper. The mount I received didn't come with instructions on how to install it. However, I was able to figure out how bottles and nuts go together. I would recommend that they put some sort of guide or simple booklet in the box on where the parts go as some people might get confused. Installation was easy and quick. I was impressed by how durable and reliable the straps are. My spare tire is a 10-ply 225/75 R15 tire that fits perfectly in the trunk without wobbling or moving. I definitely recommend this carrier.