Item No. 728937: 1/4 in Quick Connect Inline Shut Off Valve. This is used to shut off feed or outlet line to system. This valve is for the Stealth RO system or the Small Boy systems as well as any other 1/4 inch systems. Item No. 728939: 2 Way Splitter 1/4 in. This is a Y splitter for multiple reservoirs for the Stealth RO system or the Small Boy system as well as any other system that takes 1/4 inch tubing.