Gestopft muting is unique to the French Horn. The term "Gestopft" is from German and means "Stop" or "Stopping mute" in English. The sound of Gestopft is made up of various harmonic overtones and is a bit metallic. When a hornist inserts a hand into the bell of the instrument and completely cutting off the airflow, it raises semitone because the sound wave is shortened, and is almost impossible at pedal range. (For example, the final movement of Tchaikovsky's Symphony no. 6) The chief feature of BEST BRASS Gestopft is that it is "Non-transposing." It does not raise the pitch by a semitone and allows for playing the score "as is.". Of course, it beautifully achieves the Gestopft sound, and it does so in even pedal range. This technology has been welcomed all over the world, and is used in many professional orchestras and bands. Good for horns in F, Bb and F/Bb.