One month ago,
I purchased this cage for in cargo flight travel. Its sturdy an solid;a reinforced tough plastic. Secured with given screws an bolts. Locking door is solid an reliable. Although my given instructions were not the same lock it was simple enough to understand for reopening. 
My only gripe with my entire experience is to fly buy your own metal bolts to pass inspection. They are not provided, but are necessary to fly in cargo.