This mute is a further development of the Straight Mute "Vienna". Through the detachable Cup top there are two basically different timbres possible: Straight Mute for orchestra and the Cup Mute for concertinos, private concerts etc. The beautiful, lordly sound of the Cup Mute should be highlighted. This mute is dedicated to Prof. "SIR" Nikolaus Schafferer (Professor for tuba at the University of Music and Performing Arts Vienna, tuba player of the Vienna Symphony Orchestra), this gives the mute its name "SIR".