O-rings for trumpet, cornet, and flugelhorn tuning slides. Fits at least YAMAHA. Made of nitrile rubber. Set of 10. Diameter: 12mm Inner diameter: 10mm Thickness: 1mm Although only 4 are used for one trumpet, we include 2 extra in case any break or get lost. These are thinner than Yamaha's genuine ones, so the impact on pitch and resistance should be lower. The photo shows a Yamaha trumpet with these O-rings installed. To offer them at a low price, they will be shipped via regular mail, so there is no compensation. Please understand. Thank you for your consideration. 【Attention】 We do not accept purchases from those who cannot rate immediately after receiving the item. We may respond with a rating in some cases. However, this does not apply if you have explained beforehand. Thank you.