Jaco Compression Fittings
Compression fittings should only be used on fixed connections, not on moving parts... As you take a close look at compression fittings, one thing becomes immediately apparent: they are intended to prevent the pipe from moving outward from the fitting when it is compressed.
What is a Jaco fitting?
JACO fittings have a molded ferrule that is an integrated component of the nut, which eliminates the requirement for a two-piece assembly in most situations. These are designed with plastic grippers that are ideally suited for usage with polyethylene tubing.