I just made one with a $10 air gauge setup with an adjustable knob. On the turbo side is an air chuck, and on the other is a male nipple for an air chuck. Basically, we just made it universal for compressed air at our shop. We have different size caps for the turbos with a nipple epoxied in the center. Everything snaps together so as to not have to hold an air valve onto a valve stem.

 

Look at what it's made of, really doesn't cost but 5 dollars to make yourself.



I went a little bit of a different route with mine, but it worked in the end.