Chin straps are useful for those who wear a nasal CPAP mask or a nasal pillow mask but are also known as a mouth breather. If your mouth is opening during therapy you are losing CPAP pressure because the air is just escaping out of your mouth leaving your therapy ineffective. Using a chin strap will help solve this problem for many patients. The soft material wraps around the bottom of your chin and the top of your head to help keep your mouth closed so you can get the therapy you need. Please be aware that this product contains Neoprene.