Halo Chin Strap for CPAP Therapy 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 defeating the purpose 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. 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. The Regular size is not adjustable; however the XL size is adjustable. Included in this Package (1) Regular OR XL Adjustable Halo Chin Strap (Size selected at purchase) Recommended Replacement Schedule Chinstrap: Every 3-6 Months (or as needed) Tube Hose: Every 1-3 Months (or as needed) Foam Filters: Every 1-3 Months (or as needed); wash weekly Ultra Fine Filters: Every Month (or as needed) Water Chamber: Every 3-6 Months (or as needed); wash daily