Eight interlocking panels. Can be used both indoor and outdoor. Easily breaks down for storage when not in use. Made from heavy duty metal. Charcoal color. Minimal assembly required. Iconic pets metal tube playpen is a great place for you pet to play or exercise. Safety instructions: This tube pen is intended for trained pets. Supervision required. Remove any foreign object from the pet including collar, tags, and leads before placing it in the playpen to prevent possible entanglement. Do not leave your dog unattended for long periods of time. Cats and dogs that jump high are not recommended!