This grunt tube is custom made to give the diaphragm mouth caller a greater edge over elk. Includes the new Tone Selector for true back pressure making your mouth diaphragm call easier to use. Simply dial the bull sounds desired, small, medium or large. The chambered tube aids in amplifying all the sounds bull elk make. Includes a camo cover and lanyard. The chambered tube comes with a Tube Tamer for added realism. This is the tube used by Rockie Jacobsen for winning the RMEF elk calling contest. It has been field tested with great success.