This is a Warburton trumpet mouthpiece. It's a set of a top and a backbore. The size is 7, and it's a relatively new cup shape, MV, with a drill size of #26. I also ordered a symphonic and open 10 backbore with a drill size of #26 to match. Nominal values: Cup shape: Medium depth V cup Inner diameter: 16.00mm (0.630 inch) Outer diameter: 26.80mm (1.055 inch) Drill size: #26 I have many other items for sale, so please check them out if you'd like. #TPY's list of items for sale is here Type...Trumpet Accessories/Parts...Mouthpiece