Alto clarinet / bass clarinet / sousaphone neck screw. Nickel plate.
Fits alto clarinet models:
- Holton AC602
- Vito / LeBlanc 7165
Fits bass clarinet models:
- Holton BC602
- Holton BC604
- Vito / LeBlanc 7166
- Vito / LeBlanc 7168
Fits sousaphone models:
- Holton BB300
- Holton BB310