PM Exercise Pen w/Door 36"Petmate Exercise Pen w Door 36" Give your pet a safe, dedicated space to run and play with the versatile Single Door Pet Exercise Pen from Petmate. Perfect for indoor or outdoor use, this exercise pen has one double latch door that makes it easy for pets and pet parents to enter and exit the pen when needed. The Single Door Exercise Pen is made of durable wire with a solid hinge design, making it effortlessly easy to set up and fold down for