On one hand, this product gets 5 stars and on the other hand 3. The reason for this is that it does exactly what it says, it stops snoring, in my case 100%, no more snoring, my wife is super happy about this product and says that it could be a marriage saver. So it definitely does as advertised, no doubt about that. However, as a user of this product, I must say that there is quite a bit of discomfort, I did follow the instructions in the handbook, which is well written in English and detailed with pictures. However, using the product is where the issue lies. For example, I cannot close my lips, this might sound funny and like something that is a non-issue, but sleeping with my mouth closed is something that I have done all my life, the handbook even says that sleeping with your mouth open is unhealthy. This mouthpiece is so big I cannot close my lips, the gap in the mouthpiece, which is good for breathing should you need to breathe through your mouth is big, but the result is that my mouth is pretty much open, so I have to put my tongue in that gap in order keep my mouth from trying out. Nevertheless, regardless of these issues, I will continue to use this product, it's great, and everyone is at peace at night.