Abstract: The invention relates to a yarn treatment device for intermingling multifilament yarns by means of a pulsating air stream that is generated by a rotating cup ring having openings, characterized in that the drive motor and the support of the cup ring are located in the interior of the housing with the air supply channels thereof, and to a yarn treatment device for intermingling multifilament yarns by means of a pulsating air stream that is generated by a rotating cup ring having openings, characterized in that one or more nozzle inserts, through which the pulsating blown air flows, per thread run are arranged on the housing cup.