Phonak Micro Tubing2 Total Tubes (Left & Right) Fits the following models of Phonak hearing aids: Phonak Certena, Phonak Certena Art Micro, Phonak Certena Art Micro Petite, Phonak Exelia Art Micro, Phonak Exelia Art Micro Petite, Phonak MicroEleva, Phonak MicroSavia, Phonak MicroSavia Art, Phonak Versata, Phonak Versata Art Micro, and Phonak Versata Art Micro Petite. Please look at images carefully. Size of tube can be determined by looking at the end of the tube where the dome is placed. Tubes have plastic loop to help tube from falling out. It can be removed if necessary.Behind The Ear (BTE) hearing aid tubes harden and should be changed at least every six months. Many people find it beneficial or necessary to change them more frequently. BTE hearing aids become uncomfortable and more difficult to wear as the tubes become progressively stiffer. Also, it is claimed the sound transmission through hearing aid tubes deteriorates as the tubes harden. What Makes Tubes Harden? Oil from the skin and products used on a person’s hair cause tubes to harden. Additionally, people who spend more time outdoors find their tubes need changing more frequently because the UV rays from sunlight and extremes in temperatures cause tubes to harden faster.All the tubes in this listing are industry standard size #13 and fit most BTE hearing aids for adults. This Outside Diameter and a name describing the wall thickness are commonly used to identify the different tubes. * Tubes that have been modified, installed, attempted to be installed, have come in contact with a personal hearing aid or earmold or used in any way CANNOT be returned for exchange or refund because we cannot resell Personal Healthcare Consumables. Brand new fresh stock from manufacturer. All of our items come directly from the manufacturer. Nothing is old stock and no knocks offs. Official OEM products only. We are located right in the middle of the continental United States of America. Nothing drop ships from overseas or Hawaii. PaymentPayment or contact must be made within seven days or an unpaid item dispute will be opened and feedback will not be left.PayPal is our only choice for payment.FeedbackFeedback will be left once the buyer has left feedback, acknowledging that the transaction has been completed and that all is as it should be. If you don’t know how to use the feedback forum read the help section, it will guide you through it. If you have excessive negative feedback, we reserve the right to cancel your bid.ShippingAll shipments are through USPS.Almost all orders ship out the day after purchase.Return InfoReturns are not accepeted for any of our products. „According to the FDA, it is in your best health interest to obtain a professional medical evaluation before purchasing a hearing aid and you are encouraged to do so before bidding on this item. If you choose to not obtain a medical evaluation before purchasing this item, I am required by law to provide to you and obtain from you a signed written waiver of the medical evaluation, and I am required to provide to you a copy of the User Instruction Brochure for a hearing aid, review the contents of that brochure with you, and afford you time to read the brochure. You must provide to me either a signed statement from a physician or a signed waiver before I will deliver this item to you. Upon your request, I will also provide to you a copy of the User Instructional Brochure for the hearing aid or the name and address of the manufacturer or distributor from whom a User Instructional Brochure for the hearing aid can be obtained. „