The B3D is based on a scan of a Bach 3D mouthpiece with the Wedge DOC rim and cup. This is an excellent mouthpiece for players who wanting something a little shallower than a Bach 3C cup without going all the way to a very shallow lead mouthpiece. All mouthpieces in the SB line are made by doing a digital scan of the conventional mouthpiece. The cup and alpha angle are slightly modified, and a Wedge rim is programmed to produce a mouthpiece that has a feel and performance similar to the original, but with Wedge advantages. This mouthpiece has our new Double Oval Cup (DOC). The diameter of the rim and cup in the vertical dimension is 10/1000 of an inch larger than it is from side to side. This means that the oval shape of the Wedge rim is continued down to the base of the cup where it joins the throat. The DOC design, found only in Wedge mouthpieces, provides the added efficiency of a smaller mouthpiece with the big sound, clear attacks, and flexibility of the larger mouthpiece. This top must be used with a Wedge, Warburton, or similar backbore, which can be purchased separately. Gold plated stainless steel tops are available by special order, but cannot be returned. Email Dr Dave if you are interested in that option.