To get down to real parts ID, we need to know details like if the connection is female or male as well as what size and often what thread count.
As an example, a Clippard solenoid body may need a 10-32 to screw into it if not mounted on a manifold but need a 1/8" male pipe thread. Then the other end may need to be a barb to fit the tubing. But each fitting will often have two sizes, one for each end if not just a straight like 1/8 to 1/8.
Not meaning to make it sound difficult but more info is needed to get the "correct" answer and there are times when there are several correct answers if we throw in using reducers, etc.