Features: 1.Every product has a unique Manufacturing Part Number label on the inner package that proves it has been qualified,which include Part Number,Model Number and inspection date information; 2.If you have any questions about the item,please provide us the Manufacturing Part Number for checking,your profits will be guaranteed. 3.Can used in the main transformer of the trumpet,and the No. 3 tuned tube. 4.It can also be used on the horn, trombone, trumpet, sub-tone, etc. 5.Made of Copper-Nickel,good workmanship,good sealing and corrosion resistance. Specifications: Material:Copper-Nickel Color:Silver Brand name: Unbranded .