This is a signature model by Michael Massong, who served as principal player in orchestras such as the Aalborg Symphony Orchestra and the Hamburg Symphony Orchestra. It's a high-performance model suitable for a wide range of applications, from orchestral playing to solo work. Unlike the brass of standard mouthpieces, this model is made of χ metal (chi metal), which contains a high copper content. Also, unusually for a trombone mouthpiece, it features a scooped-out cup interior and LS (lip space) processing. 【Product Information】 ◆ Trombone Mouthpiece for Large Bore Manufacturer: willie's Model Number: MASSONG 5TM 6.8 χ LS GP / Gold Plated (Rim Inner Diameter/25.50mm, Throat Diameter/6.80mm, Weight/197.0g) 【Condition】 This is the Michael Massong signature model. It has a medium-heavyweight body, but it's designed to produce sound efficiently even without much force, making it easy to handle even for those who usually use lighter mouthpieces. There are a few shank scratches, but the gold plating remains beautiful, and the rim and body are in excellent condition. This model uses χ metal with a high copper content and features a luxurious gold-plated finish. Please check the photos for details.