OK- first my problem was teeth grinding at night, then snoring. Finally my wife was worried- you gasp at night she said. I hear you quit breathing, then you gasp. Over and over. Dang. I know what that is. Apnea, and a ticket to a heart attack eventually. Enter PureSleep. Their concept is correct. The lower jaw slacks back, and you are snoring and eventually cutting off air. Rather than wear a forced air device (CPAP), I setup the PureSleep with the center settings, normal. That wasn't enough (still snored and gasped). So I re-heated it, moved the lower jaw out one notch. This pulled my lower jaw out another 1-2 mm. Not enough to give me TMJ, but enough that in the morning I could not cleanly bite down, which meant it was holding my lower jaw out slightly. When you put it in you have a slight underbite. Now I no longer gasp and my snoring is mostly gone- heavy breathing but not the freight train. the dentist loves it because I am no longer busting old fillings (from grinding). Easy to clean- replace it once in a while since they get worn out...