This is a nice old hard rubber clarinet mouthpiece measuring .050″ (1.27 mm). From the stamping of the facing on the table, I’m thinking this was made by Woodwind Company of NY for Buffet, as a jazz-leaning clarinet piece. That’s just a guess. I’m not an expert on clarinet mouthpieces. Let me know if you know more about it. It plays well with a warm, rich tone and plenty of power.