The V.E.T.T. system contains a spring tuned to the precise dimensions inside the specially made mouth piece. The spring creates more volume, stabilizes higher notes, has raspier low growls and easier octave changes. Less than 18” in overall length makes The Threat easier for packing. The Threat features a 1” mouth opening and tapered lip adaptor, as well as a vibration dampener (Tube Tamer) on the inside of the tube. Comes fully assembled and ready for use with your favorite mouth diaphragm.