I used this because I have a metal allergy. It's in beautiful condition with no scratches or dents. KELLY-24AW Tuba Mouthpiece Material: LEXAN (polycarbonate resin)... LEXAN is a material known as polycarbonate resin, boasting unparalleled impact resistance and high heat resistance up to 125°C. Surprisingly, it's an excellent material with more strength per weight than iron. 24AW ■Diameter: 31.24mm ▪️Weight: 32g ■Cup Depth: MEDIUM ■Equivalent to BACH 24. Below is BACH's reference information: Cup Type = AW / Cup Depth = D (Deep) / Diameter = 31.25mm / Rim = W (Thick) / Characteristics = Loud sound, dark, resonant, excellent mouthpiece ■Made of LEXAN (polycarbonate resin) The material is LEXAN (Lexan). It has water-like transparency, unparalleled impact resistance, and high heat resistance up to 125°C. It comes in a wide variety of types and has the smooth feel unique to resin. It doesn't get hot or cold even when used outdoors. Recommended for marching bands, school festivals, and event performances. The transparent colors can be used to check embouchure, etc. It's hard to deform even if dropped and is very durable. Recommended for those with metal allergies. It's less likely to produce metallic sounds when switching mouthpieces during performance. Also used in the 5th piece of competition set pieces, etc. ■KELLY Tuba mouthpiece ■24AW ■Diameter: 31.24mm ■Throat: XL ■Cup Depth: MEDIUM ■Equivalent to BACH 24. Below is BACH's reference information: Cup Type = AW / Cup Depth = D (Deep) / Diameter = 31.25mm / Rim = W (Thick) / Characteristics = Loud sound, dark, resonant, excellent mouthpiece Retail price: ¥12760 #MetalAllergy #Tuba #TUBA #Mouthpiece #WindBand