This LayZSpa Screw Valve is designed for the 2021 liners and above. It screws directly into the LayZSpa liner and is used for inflation, using an inflation hose, and caps off the liner to prevent air from escaping. This pack contains 1 replacement screw valve. Compatible with: Hawaii AirJet Hawaii HydroJet Pro Honolulu AirJet Majorca HydroJet Pro Maldives HydroJet Pro Milan AirJet Plus Palm Springs AirJet Palma HydroJet Pro St. Moritz AirJet.