Train hunting dogs and I haul a lot of buckets, guns, *****'s and mainly a gunner kennel which is the best you can get for safety but its huge! That being said I got the rack with the XL case and 1 small case and the kennel fit perfectly, I definitely could have done dual XL cases with no issue. Install took about 2 hours or so, you need a drill for this, I'm sure you can use a wrench however, that will take extremely long. Overall this is everything I need, quality was perfect, strong and sturdy. The cases are a godsend for all the things you don't want tumbling around in the bed. The only thing that makes this 4 stars is I was missing 2 "T" screws for the overhead bars.