Item No. 728932: 1/2 in. Quick Connect x Garden Hose Connector - Feed Valve. This is the replacement feed valve for the Merlin GP RO system as well as the Tall Blue system. Item No. 728935: 1/2 in. Quick Connect Inline Shut Off Valve. This is used to shut off feed or outlet line to system. This valve is for the Merlin GP RO system as well as the Tall Blue system. Item No. 728936: 1/2" Quick Connect Union Connector. This is to connect 2 lengths of equal sized tubing together for the Merlin GP RO system as well as the Tall Blue system.