This is a double layer magic dome set of ReSound open-air hearing aid domes with 5 or 10pcs. We have three different sizes which are Small size (6mm), Medium size (9mm), and Large size (12mm). You could find the seven variations in different combinations in the middle side of this page. These domes could be used with Resound open-air hearing aids, or Signia, Phonak, Otofonix, LifeEar, Retone, Beltone, Advanced Hearing, Austar, NewSound, Hearing Assist or MD hearing aids. These are NOT suitable for RIC models. We suggest you to start with the mixed set ASIN# B07HB31CK9, this will help you find the most suitable size for your ear canal. If the dome is too big, your ear canal will feel pressure and will not be comfortable. If the dome is too small, the sound will be leaked and you will hear a terrible squealing. So it's important to choose your suitable size carefully in advance. If you already know which size will be suitable for you, then please directly purchase a set with your suitable size. Hope you enjoy our products and service. We sincerely look forward to your good reviews. Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.Disclaimer: While we work to ensure that product information is correct, on occasion manufacturers may alter their ingredient lists. Actual product packaging and materials may contain more and/or different information than that shown on our Web site. We recommend that you do not solely rely on the information presented and that you always read labels, warnings, and directions before using or consuming a product. For additional information about a product, please contact the manufacturer. Content on this site is for reference purposes and is not intended to substitute for advice given by a physician, pharmacist, or other licensed health-care professional. You should not use this information as self-diagnosis or for treating a health problem or disease. Contact your health-care provider immediately if you suspect that you have a medical problem. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease or health condition. Amazon.com assumes no liability for inaccuracies or misstatements about products.