Sixteen HDPE panels clip together in whatever shape the room allows, so the pen can run straight along a wall, wrap a corner or close into a square. Each panel measures 21 by 31.5 inches and the walk-through door opens 14.5 by 30.5 inches. HDPE keeps the surface smooth enough to wipe down and tough enough for a dog that leans on it. Suction cup feet grip smooth indoor flooring and ground stakes are included for grass, so the same pen works in a living room, beside an RV or at a campsite. The panels break down flat for transport and the complete set weighs 20.5 lbs. White keeps it visually quiet in a room where a metal pen would dominate.