Bach Symphonic trumpet mouthpieceThe Symphonic Series uses the Classic Series cup designs and opens up the throat and backbore negating the need to have a Classic Mouthpiece reamed by hand which can create inconsistencies in playability and tone. Symphonic Series mouthpieces are completely made on CNC machines creating a precise mouthpiece every time. Currently only stocked with 24 backbore and throat. Other throat options available to order.