"Taking bugling to the next level, the Rocky Mountain Hunting Calls Rogue Bugle Tube combines the inventiveness of Rockie Jacobsen with the hunting prowess of Steve Chappell. The V.E.T.T. system contains a spring tuned to the precise dimensions inside the specially made mouthpiece. This spring creates more volume, stabilizes higher notes, maintains higher pitches, and requires less air pressure to operate. Other highlights include a 1.5"" mouth opening, a tapered lip adapter, and a vibration dampener on the inside of the tube. Measures less than 18"" for easy packing. The Rocky Mountain Hunting Calls Rogue elk bugle call comes fully assembled and ready for use with your favorite mouth call.Manufacturer model #: 141. V.E.T.T. system contains a spring tuned to the mouthpiece Creates more volume, stabilizes higher notes, and maintains higher pitches Requires less air to operate 1.5"" mouth opening Tapered lip adapter Vibration dampener on the inside of the tube Measures less than 18"" for easy packing Fully assembled"