This is an older style of hearing aid most commonly used by Bernafon. The dome and base are connected with a transparent tube instead of a wire. If your hearing aids use a wire instead of a tube, please consult the Dome changing with RITE (Receiver in the Ear) hearing aids article instead.
This image and video shows how to change domes on BTE Slim Tube hearing aids
Domes are available to purchase on our official website: Hearing Aid Supplies Archives - HearingLife Shop