Signia (Siemens) HF3 wax filters are colour coded red for right sided hearing instruments or blue for left sided hearing instruments. Each wheel contains 15 wax filters, 3mm in diameter, which are used to protect receivers from wax and debris. Please take care when ordering that you know which type of was filters you require. If in doubt please ask or alternatively seek advice from the company that supplied your hearing aids. If you order the wrong size / type of wax filter we are happy to replace with the correct item, if the product is returned unopened and in a re-saleable condition. We cannot however, accept opened packets.