This is a thumb ring (stainless steel) for use on the tuba in St. Petersburg. This product allows you to bring your thumb about 15mm closer to the lever compared to the original ring, making fingering easier by reducing the need to force your thumb. For those who find it difficult or undesirable to attach a coin to the lever or have a repairman reposition the ring due to cost or appearance, this product is very convenient as it can be used immediately by simply replacing the original. Furthermore, this product features a cat motif design. Cat motifs are often chosen for their meanings of "warding off evil," "repelling disaster," and "bringing good luck." Why not adorn your instrument a little with a good luck charm or accessory? Product Details: Inner ring diameter: 35mm, Wire diameter: 6mm Threaded section: M6 x 15 Weight: Approximately 32g (Original product: approximately 27g) Material: Stainless steel Made of stainless steel, so it will not rust or have its plating peel off. ※ This product is a handmade item created by the seller. It may not be suitable for those seeking perfection, but it is a unique product for those who appreciate originality, and I highly recommend it.