It was purchased for me. My husband says it works. Reduces snoring to heavy cold breathing. And yes I said cold. The exhalation seems to be noticeably lower than your body temperature.I was surprised how simple and small device would replace my CPAP machine. I wake up refreshed and snoring has stopped. I have been using Bongo Rx for a little over a month.After buying a number of products that didn't work, and even undergoing a painful procedure to cure my snoring, I was quite shocked when I woke up the first night having used this and realizing that it actually worked and I had barely snored the night before, and have had about a month of greatly reduced snoring with it. On that count -- the most important one -- it's great. It's not super comfortable to sleep with, but I have found it tolerable, and is far better than anything else I've used. This is very much worth trying and perhaps I should have given it 5 stars because the benefits far, far, outweigh the negatives, but . . .On the downside, while it is supposed to last for 90 days before needing to be replaced, I have used my pair for only around 30 days before it lost its texture and began falling out of my nose at night. I should add that the price being charged on Amazon is nearly double what I paid for my starter set.My wife bought these for me since my CPAP is on the recall list due to the death foam. She said there was no decrease in snoring compared to no CPAP or wearing these. I also woke up every 1/2 hour. On the plus side, I did feel some exhalation resistance as advertised, but this was not enough to keep my airway open.