John Grey Autocrat 17 Trumpet Mouthpiece Please note that we judge the condition of this product to be: Used Good Please see pictures for quality, There will be some wear. This listing is for a John Grey Autocrat 17 Trumpet mouthpiece. We estimate that is has 95% of its plating. These are the approximate measurements rounded up. Cup Diameter = 30.5mm, Rim Width = 7.5mm, Cup Depth = 9mm, Shank Top Diameter = 12mm, Shank Bottom Diameter = 10mm, Shank Length = 40mm.