With the MP CL 4C Yamaha offers you a mouthpiece with excellent playing characteristics for Bb clarinet. The general sound is good, and beginners and advanced players alike can make great use of this mouthpiece. Standard Series Yamaha offers an expansive assortment of mouthpieces in their Standard series. These mouthpieces are fashioned from phenol, a type of high-quality synthetic material. Their design is derived from the Custom series mouthpieces, which guarantees good, consistent playability. The Standard series mouthpieces are easier to play than those of the Custom series, making them excellent for beginners. For many of the Standard mouthpieces you can choose from a range of sizes. mouthpiece for Bb clarinet size: 4C good playing characteristics balanced sound over entire range suitable for beginners and advanced players