I recently got a cheap set of conshelf XII regs and have been told they are still servicable and that they are as good a reg as many of the new ones available. I just don't like the feel of the second stage in my mouth - the exhaust part (I don't know the proper name of it) pushes onto my chin and its fairly uncomfortable. Is it an option to change the second stage only? It seems that second stages are always sold with a first stage, can you get a second stage on its own? While I am asking so may questions, what is the difference between a primary second stage and an occy second stage apart from the colour - could I just use an occy second stage as my primary?