Feature: 1. PRESSURE RELIEF: This valve can help the performer reduce mouth pressure during trombone playing, improve comfort and control performance. 2. BRASS MATERIAL: This pressure relief valve is made of excellent brass, ensuring good durability and reliability, corrosion resistance and wear resistance. 3. SKILL CORRECTION: Can help trombone players correct the wrong mouth posture and techniques, improve sound quality and playing techniques. 4. GOOD COMFORT: Adopting ergonomic design, this pressure reducing valve can effectively reduce discomfort in the mouth and face during performance. 5. EASY OPERATION: This pressure relief valve is suitable for various models of trombones, easy to install and adjust, suitable for performers of all levels. Specification: Item Type: Trombone Pressure Relief Valve Material: Brass. Package List: 1 x Pressure Relief Valve1 x Storage Box