A device (2) for insertion into an ear canal of a mammalian subject defines at least one sound path (16) therethrough. The second path (16) has an attenuating arrangement (14) therein which has a first configuration having a first level of attenuation and a second configuration having a second level of attenuation, higher than the first level. The attenuating arrangement (14) is such that upon application of an electrical control signal thereto, it is caused to change between the first and second configurations. The attenuating arrangement is stable in both first and second configurations such that the attenuating arrangement only draws electrical current from a power source when changing between the first and second configurations. The device further comprises a receiver (36) for receiving a command signal (34) from outside the device such that receipt of the command signal (34) causes the electrical control signal to be applied to said attenuating arrangement.
