MidWest Homes for Pets Exercise Pen Accessories Exercise pen top fits ALL MidWest models & most standard metal exercise pen brands, the x-pen top measures 4 x 4 feet w/ 1.5 x 6 inch mesh spacing Exercise pen top is compatible with metal exercise pens with doors & w/out doors. The pet pen must be in a square configuration for top to fit effectively Includes 8 thumb-snaps to securely lock the metal top to the exercise pen keeping intruders out & "escape artists" inside the exercise pen Metal top is easy to install w/ no tools required & is hinged down the center for easy half-access into the dog pen. The top features a durable e-coat that prevents rust Playpen top provides your dog w/ healthy air ciculation, great visibility & includes a 1-Year Manufacturer's Warranty