The Mute Holder is designed for cornet, trumpet, trombone, or French horn mutes.Rings are covered with Specially Formulated Foam Padding.HA100 has 270° of ring swivel. Designed for cornet, trumpet, trombone, and French horn mutes.Attaches to most music and microphone stands with a shaft diameter of 8 mm - 30 mm (0.31" - 1.18").