Okura Mute for Trombone

Quoted from the official source below:

[Practice Freely Every Day]

Introducing the handmade practice mute, Kokuratmute, designed to pursue a comfortable sound and aid your improvement without worrying about compromising your playing technique.
It effectively muffles sound, providing a comfortable experience that makes you want to play endlessly.
■ Suppresses unwanted vibrations and eliminates uneven tone.
■ The main body can be opened and closed for easy internal cleaning.
■ Two air chamber sizes can be selected, allowing for practice with accurate pitch across a wide range, from pedal tones to high notes, by utilizing the difference in resistance.
By using the included pipe, you can change the resistance.
While the idea is to allow you to discover your own practice methods using two different levels of resistance, this design also makes it usable as a practice mute for alto trombones and flugelhorns.