This is a Jardinet trumpet mouthpiece, favored by professional studios and big band players. It's a Jardinet 3M with the slightly larger engraving from before the transition to the smaller new logo. Jardinet mouthpieces have become difficult to obtain in recent years. The inner rim diameter is slightly larger than a Bach 1C. The rim is semi-round with a normal thickness. The rim shape slopes gently towards the outer edge. The outer rim diameter feels like it's between a Bach 1 and 1-1/2. The cup is a gentle UV cup, with a U-cup shape at the top and a V-cup shape at the bottom. The depth is about the same as a Bach E. The throat is #28 (3.57mm). The backbore is about halfway between a Warburton 3 and 4. It produces a warm and rich mid-low range and a focused, brilliant, and powerful sound. The balance from low to high notes is good. Recommended for combo, solo, and switching between instruments in a wind ensemble for pop music performances.