GN ReSound SureFit 2C Receivers are precision-engineered hearing aid receiver wires. These replacment hearing aid receivers are designed for compatibility with many GN ReSound hearing aids (excluding the ONE and Omnia which require GN ReSound Surefit 3 Hearing Aid Receivers), offering exceptional sound quality and easy installation for a more comfortable and personalized hearing experience. To find the size you require, remove the dome from the end of your receiver wire and you should see some letters and numbers printed on the end of the receiver wire. These correlate directly to the size you require. So, if your receiver reads '2M' and is the colour red, you need 'Left Ear, Medium Power, Size 2' as the colour red refers to the right ear, the number 2 refers to the size/length and the letter refers to the power/strength of the wire. If the end of your receiver wire is blue, then that is the wire for your left ear. If you have any difficulty fitting this part, please contact your local audiologist for assistance.