MidWest Homes for Pets offers a variety of exercise pens that are durable and affordable. Exercise pens are great playgrounds for your pets whether indoors or outdoors. Black E-Coat Exercise Pens are made of a durable black electro coat finish for long lasting protection from corrosion and rust. Stability features included with the exercise pen are ground anchors to help secure the pen in place, corner stabilizers add rigidity and main configuration.