A device designed to present a specific mechanical impedance to a bone vibrator, applied with a specific static force and equipped with a mechano-electric transducer, to enable an alternating force level at the point of contact between vibrator and mechanical coupler to be determined. Also known as an artificial mastoid, it provides a mechanical load to a bone vibrator that approximates that of the average human mastoid process. The standard (IEC 60318-6) specifies such a device.