If one needs to replace the Sennheiser RS120 ear pad or to access the components underneath, such as the batteries or the speaker, you need to remove the ear pad initially. This replacement won’t take too long and you won’t need any tools for this removal.
Grip the ear pad with one hand and steady the headset on the other.
Twist the ear pad counterclockwise, then lift the ear pad off after about an eighth of an inch of the turn.
Replace the old ear pad with a new ear pad.