These speakers are suitable for Unitron D Moxi hearing aids from the Discover series. Below you can find how to replace the speaker, also called receiver: You will also find the instructions written out here: How do you replace a speaker in a hearing aid? You grasp the hearing aid. On the side where the brand of the device is on, so with the Silver rod you move the pin to the side. Grasp the speaker with your thumb and index finger and pull the speaker out of the hearing aid. Then take the new speaker and press it into the hearing aid. So with your finger on the pin to get the pin back in the right place. Finally, check whether you have really pushed the speaker down properly. https://youtu.be/oh7SCqSeVCA