The rims of the Boone Mouthpieces offer an amazing amount of customization options.  They can be standard titanium, part of a one piece black acrylic unit, or could be decked out with options such as your fingerprint or other artwork lasered in, mokume gane inlay or even a 4.6 billion year old meteorite inlay!  Jewelry for your trumpet.

They are laser engraved with the Boone Zone System size, which can be found in the Sizing Chart.  The rims stay attached to a particular cup, and the combination can be unscrewed from the shank.