I bought two of these to put on my rig. My wife complained that her tori bone was getting painful after using a default mouthpiece on a scubapro regulator. I donated one to her. It took a couple of minutes to fit the mouth piece and installed on the regulator in about the same time. My wife praised it so highly because it helped with the tori bone pain and TMJ. I find that I can rest my jaw and the mouthpiece stays in my mouth with no effort.
