Outstanding beautiful French Horn Straight Mute effect, non-transposing. No transposing whatsoever. The “C” you play open horn, you obtain the same “C” in perfect pitch when you place in the mute. Ideal for solo or section work. Willie Berg invented Stone lined Mutes in 1935. They are the finest Brass Instrument Mutes available in the World. Stone lined Mutes play perfectly in tune and are easy blowing. For the perfect professional sound all the time, our line of Stone lined Mutes offers many different models to produce outstanding various tonal colors for the Brass player. Included in the many Stone lined Mute features that allow the outstanding colors of sound is the secret formula used to line each and every Stone lined Mute.