Oticon MiniFit Receiver Speakers are available in different powers and lengths; length is denoted by a number, while the left ear is blue and the right is red. These are compatible with the following Oticon hearing aids: -Real -More -Play -Zircon -OPN S -OPN Play -OPN NOTE: Before purchasing ensure that you are aware of how to safely remove and replace your new receivers. Hearing Aid Accessories are not responsible for any damage to hearing aids when you replace or fit spare parts.