I bought a generic quick disconnect adapter from Amazon before for my Iwata Eclipse HP-CS and had air leak issue. So I bought the Iwata adapter and it works like a charm. It costs more but it's the quality I can trust. I think it's worth the money on avoiding the hassle; very happy with the product.
Works very well. Saves wrenching airbrushes on and off the hose!
Obviously a must if you bought the set, but have many airbrushes. Will be back for more.
This disconnect is handy for my second airbrush there is a rubber seal inside of the threaded end that creates the seal to the airbrush.