Easy set up and use Heavy-duty PVC and polyester 3-ply side walls for prolonged durability Liner is supported by an inflatable top ring Built-in flow control drain valve makes it easy to drain by attaching the valve to a garden hose Extra strong side walls of this pool are constructed with Tritech, a 3 layer reinforced material with a polyester mesh core encased between two layers of high gauge PVC material for reliablity