I was advised to get one of these by the doctor to prevent snoring due to feeling so tired after waking up (the brain doesn't oxygenate properly with heavy snoring apparently). I went for this model because it adjusts and had great reviews. Well Im not disappointed. It arrived the day after (express shipping) and immediately at arrival I molded it. Went wrong twice, but I finally got it. I did twiddle with the settings the days after and ended on a low advancement setting (number 3) which is working really well in eliminating snoring (according to my hubby) Please please don't overdo it on first use, in terms of how far out you have it push the jaw. I’ve learned it the hard way that it's not a great idea. Small increments is the way to go.