To create the Mega Tone, Selmer started with genuine Vincent Bach mouthpiece designs, then more than doubled the outside mass. This darkens the sound and allows you to play at higher dynamic levels without distorting. Mega Tone slots extremely well so pitches center dependably. A slightly larger throat affords less resistance and greater flexibility. The result is a warmer, more powerful sound that's perfect in the concert hall, and adds a new dimension to pop and jazz playing.
See the following web page for further details on Bach Tuba Mouthpieces.
Bach Mouthpiece Guide