Perantucci tuba mouthpieces are available with the following shanks:
No indication: Large shank, for modern instruments with large receivers: (ø = 15.2 mm)
„S“ models: For intruments with small receivers: (ø = 14.8 mm)
Standard large European shank is recommended for most mouthpieces.
The Perantucci S shank is recommended for instruments that have smaller receivers or those which have high resistance