Mouth leaks are a common problem in CPAP therapy. That "cotton-mouth" feeling is a tell-tail sign that your CPAP therapy is leaking out of your mouth as you sleep. Simply closing the jaw with a chinstrap isn't enough for most people because air still escapes through the lips. Believe it or not, many people use tape or even denture cream to seal their lips! There's a much easier solution-a comfortable chinstrap that closes the jaw and moves the "fleshy" part of the chin up about a half of an inch to prevent air from escaping through the lips. 100% cotton material is light, cool, breathable, and comfortable. It also stretches less than other fabrics, so a good cotton chinstrap will deliver all the tension you need right where you need it-on the bottom of your chin. A huge problem with other chinstraps is that they're made out of flexible, non-breathable material, like Neoprene, so there's no way to deliver tension where it's needed. And who wants to wear Neoprene against their skin all night?Pur-Sleep