Tuning rings purchased from Ciel G. They sounded great when I tried them out, but I ended up buying multiple barrels at the same time and haven't had a chance to use them. They reduce the deterioration of sound quality when pulling out the barrel, so please consider them if you need them. These are completely unused. Retail price is 2900 yen. Here is the product description from the store: Ciel G, Clarinet Tuning Rings Size: For Bb and A clarinets Condition: New Quantity: 1 pack (0.5mm - 1 piece, 1mm - 2 pieces) When the pitch goes up, you pull out the barrel a little. The tube becomes longer and the pitch goes down, but gaps can form where condensation accumulates, and the barrel can wobble. Also, the inner diameter of the bore changes, which can make it a little harder to play. Tuning rings are the best solution for these problems. Ciel G's tuning rings include 1 piece of 0.5mm and 2 pieces of 1.0mm, allowing for 5-step adjustment: 0.5, 1.0, 1.5, 2.0, and 2.5mm. Simply insert them between the barrel and the upper joint to restore the inner diameter to its original shape. If you have any questions, please ask before purchasing. If you would like to purchase multiple packs, please contact me. Please ask if you have any questions. Tuning ring set for Bb and A clarinets, sizes 0.5-2.5mm, 4 pieces in total. - Brand: Ciel G. - Product Name: Tuning Rings for Bb & A Clarinets - Set Contents: 0.5-2.5mm Set - Sizes: 1.0 mm 2 pieces, 1.5 mm 2 pieces - Country of Manufacture: Japan Thank you for looking.