The most versatile, free blowing, in tune practice mute available. This is not a warm-up mute, due to its adjustable resistance and adjustable tone, this mute can be used to practice in any environment. The tone and volume may be adjusted simply by moving the resistor further into the mute. Each 10mm setting offers the player a different colour of sound and volume. with the resistor removed, this mute can be used as a quiet straight mute. Intonation and pitch is maintained throughout the register. For trumpet or cornet. - the manufacturer