These valves are meant to be screwed into pvc. Often used with a linear air piston pump to run an air loop around a room filled with aquariums. Build your own custom gang valve using these. These last a lifetime and are used by most fish stores and fish breeding facilities.
Threaded Metal Valve
Precise Air control
Use a 3/16th drill bit, then insert valve into drill chuck and screw in slowly being careful not to over tighten. Use a clean cut piece of airline tubing when attaching. Periodically check for hardened aquarium airline tubing creating a loose connection.