A large bass trombone mouthpiece. • 28.91mm cup diameter. • 8.08mm (0.318") throat bore. • Gold plated. Orchestral players who play a 60, Bach 1, or larger mouthpieces will love the feel of the Griego ".5." Most bass trombone mouthpieces are unbalanced, which causes a wide array of sound widths and tonal colors throughout the different registers. We have paid very close attention to the balance between the cup, throat, and backbore of our mouthpieces. The end result in the ".5" is a larger mouthpiece that maintains tonal color no matter the tessitura. The upper register maintains the core sound without becoming diffuse. The lower register is full with plenty of energy in the sound. The larger cup size of the .5 allows the player to increase the size of the sound as they descend in range. Sleek "Deco" style exterior is heavier than traditional models, allowing for a darker, more focused sound. - the manufacturer