Heavy heavy duty. We had this run custom built and wanted to add nice dog houses inside for when our dogs had puppies. We've decided not to go that route. So it's for sale for less than we paid for it or best offer. It is very well made to last a lifetime. It is 21' long. 7 runs for small to medium dogs. The runs are 35" wide and 35" tall 7' deep. 18" ledge on front. Come look at it and make an offer