I bought this because it was the only chin strap in regular stock on Amazon.ca, meanwhile Amazon.com has a wide array of them to choose from. I use a CPAP machine due to sleep apnea. I use a nasal mask which means every once in a while at night, my jaw will relax, opening my mouth, and breaking the pressure, which in turn defeats the purpose of the machine. So I bought this strap in the hopes that it would keep my jaw shut while I slept.
Pros: It was delivered on time, and was a strap that could be fixed around something.
Cons: It came in a crushed box, but since it's not delicate, that's not too much of a problem. It also came with no documentation, aka cleaning instructions or how to put it on, that being said, it is pretty straightforward. Out of the box it looked like maybe it had been out of the box out in the open at some point, and had accumulated some lint on it.
There's a spot on it where the two Velcro hook sides are attached, and I'm almost certain this is not intentional and more due to shoddy manufacturing. Since no documentation was provided I'm unable to tell if this is the case.
My biggest gripe with it, is that its design is asymmetrical. Which is a problem considering it's supposed to be used on a head, which is for the most part, symmetrical.
It also felt like after a couple of hours in bed sleeping, the strap would have slipped off my head, since it really had no way of staying in place, besides being extremely tight and uncomfortable.
Lastly, it was tight and uncomfortable. I have a somewhat chubby face so it scrunched my face up to resemble that of a Pugs. A person with a less chubby face may not experience this problem.
Bottom line, I didn't even try to sleep with it on due to how uncomfortable it was off the bat. I'm going to see if I can find something more medically approved and more comfortable.