※ I have described price negotiations, etc., in my profile. Please check it in advance. This is a custom part created to modify a general rotary tenor trombone and enhance its sound and resonance. This is the small size. We received feedback that the change in blowing feel was significant when used, so we made the outer diameter slightly smaller to reduce the change in blowing feel. The effect is slightly reduced, but I think the change in blowing feel is also reduced. To use it, simply remove the rotary cap, insert it into the inner lid, and close the cap. It can be easily attached and detached. This is made of brass and aims to enhance the sound and resonance. The diameter is about 19mm and the hole is about 10mm. The thickness is about 0.3mm. It should fit most general rotary instruments. (It is handmade, so there will be some errors and it is not perfectly circular.) I created this with the intention of using it on a trombone, but it can also be used on other rotary instruments such as tubas and horns if it fits. (I have confirmed the sound changes on trombones, French horns, tubas, rotary trumpets, and German tenor horns.) I believe it is possible to make some changes to the instrument, but there is a compatibility issue with the instrument and the player, and the intended effect may not be achieved, or a completely different effect may occur. Please be aware that a positive effect is not always guaranteed. Also, I am selling this elsewhere. I will give priority to the person who purchases it first, so please be aware of this. ps Please consult if you wish to purchase multiple items. 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