Rocky Mountain Rogue Bugle Tube Contains a spring tuned to the precise dimensions inside the specially made mouth piece ;The spring creates more volume, stabilizes higher notes, makes raspier low growls and allows for easier octave changes ;1 1/2"" mouth opening ;Ready for use with your favorite mouth diaphragm ;Vibration dampener on inside of tubetable.productattributes, .productattributes td { border-bottom: 1px solid #ddd; border-collapse: collapse; padding: 2px; text-align: left; } Item Category Code: 4800 Product Group Code: 4800D Inactive: No