TMS Kobo Original Acoustic Improvement Goods Rotary Spacer-kun (Titanium) ver2 Limited production and workshop exclusive As a model change, the materials have been reviewed to produce a more resonant sound. However, as there is a tendency for the sound to become slightly harder, heat treatment has been applied. This is an acoustic improvement good to be inserted between the rotary caps of a horn. It changes the ease of sound production and resonance. It can be used with Yamaha, Alexander, and Holton horns. It is also likely usable with tubas and trombones. Outer diameter 21.5, thickness 1.5, hole diameter 10.5 Made of titanium Due to the increased cost of materials, the regular price is now 3000 yen.