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.Suitable for treble, alto, tenor, B flat, E flat saxophone, clarinet.4.Expands outwards to provide better finger grip.5.Compatible with all standard rubber and plastic standard saxophone mouthpieces. Especially suitable for musical instrument repair shops.6.Exquisite craftsmanship, sparkling and charming.7.Made of copper, it won't peel off paint and is durable.Specifications:Material: CopperColor: GoldenBrand name: BQLZRSize:Length: 28mm/1.1inchThread Diameter: 4mm/0.16inchWeight: 30 gPackage include:10 x Saxophone Neck Screws