The invention provides curable ink compositions that are inkjet printable and that adhere to a variety of substrates, for example, glass and polymer. The hearing aid apparatus is based on the bone conducting principle for bone anchored hearing aids and includes a vibratory generating part that is mechanically anchored by means of osseointegration in the skull bone at the deaf side of the patient and arranged to transmit vibrations through the skull bone from the deaf side to the inner ear on the other side of the patient. The contactor module is slideable with respect to the printed circuit board between an actuated position where the set of contactor members contact the traces and a deactivated position where the set of contactor members do not contact the traces. Also, the LSD is installed in the vehicle to the rear of a transmission. The microphones are placed front-and-back or side-by-side, or a part of the microphones are placed side-by-side and the other microphones are placed front-and-back with the part of the microphones.