Wall Pet Door for Cats and Dogs with 3 Flaps Telescoping TunnelThe Wall Becomes a Passage Homes with pets often need a way for cats and dogs to move between spaces. This wall pet door creates a fixed opening that pets use during feeding time, outdoor access, and rest periods. The three flap layers move as pets pass through the frame. Structure With Adjustable Tunnel The pet door features a steel frame paired with an aluminum closing panel and a telescoping tunnel. The tunnel adjusts to wall thicknesses between 4.