PSK PET MART Single-Door Folding Metal Dog Crates: Ideal for Puppies, Small Breed Dogs, Cats, Kittens, Rabbits and (Adult) Guinea Pigs, PSK single-door folding metal crate offers exceptional convenience. Use the metal crate for anything from potty training or house training to reinforcing house rules and boundaries-or simply as a safe, secure place for your pooch to rest and relax. Choose a crate that will comfortably accommodate your adult dog or the size of your puppy once fully grown.