※ Information regarding price negotiations is listed in my profile. Please take a moment to review it. This is a custom part designed to modify a standard rotary tenor trombone, with the aim of enhancing its sound and resonance. To use, simply remove the rotary cap, insert this part inside, and replace the cap. It's easy to install and remove. This is made of brass, intended to amplify the sound and resonance. The diameter is approximately 22mm, with a hole of about 10mm. The thickness is about 0.3mm. It should fit most standard rotary valves. (Due to being handmade, there may be slight variations and it's not perfectly circular.) While designed for trombone use, it may also work with other rotary valve instruments like tuba or horn, if it fits. I believe it's possible to make some kind of change to an instrument, but it depends on the instrument and the player. The intended effect may not be achieved, or a completely different effect may occur. Please be aware that a positive effect is not guaranteed. Also, this is for sale elsewhere. The first person to purchase will be given priority, so please understand. ps If you wish to purchase multiple items, please inquire. You can get a discount of 150 yen for each additional item, up to a maximum of 6 items. ※ The instrument used in the installation example is a V.Bach 42B. #FK Tone Disc Search terms: Trumpet Euphonium Tuba Bass