The Lust Auto-Seal hose valves are great for all glass hookahs. Made of food grade aluminum, these valves are sold in pairs and are a great way to turn your hookah into a self-sealing double hose. Simply place these valves in the hose ports and plug your hoses into them and there you have it... A dual hose hookah with Auto-Seal. This means that you and a friend can smoke your hookah at the same time without having to worry about the other person plugging the hose while you are smoking. A ball bearing inside the valve will do that four you. You can also use these as a purge valve instead of the provided glass purge valve which comes with all glass hookahs.