An adapter for inserting into a carton containing a non-reel coil of filamentary material or wire has a shaft-receiving sleeve supported by a box structure. The background calculator is configured to calculate a first background signal in which a speech signal is removed, based on the acoustic signals. Two engaging members, which are capable of being removably secured to the exterior surface of the back part, are provided on each side of the abdomen part and spaced apart from each other in a longitudinal direction along which the abdomen and back parts are arranged. The sensor provides information that correlates to blood flow in the renal artery.