Sound booster for trumpet mouthpieces. This item has no lacquer. When attached to a mouthpiece, it makes it easier to transmit lip vibrations to the bell, resulting in a more vibrant tone. It provides the same effect as using a heavy mouthpiece. I had this custom-made when I was young. It is made from solid brass and was used with mouthpieces from Bach, old Yamaha, and GIARDINELLI, among others. Please note that due to slight variations in the cup and shank sizes of different mouthpieces, it may fit loosely or not at all. This is an old item, so I am offering it at a low price. If anyone is interested, please let me know. Thank you. m(_ _)m