A replacement for the inflatable liner supplied with your Lay-Z-Spa Miami AirJet. The liner is the hub of your Lay-Z-Spa. It's the area of your Lay-Z-Spa that is filled with water and connects to the heater pump. It also contains the integrated massage jets that provide a relaxing spa experience. This liner does not include replacement Screw Valves The replacement will be smaller than the original once you have inflated it. The reason being, this is made from vinyl which expands over time from the ambient air temperature and the heat of the water. Once fully expanded, this will look the same as before.