For use with Shimano Nexus SG-8R20 internal hub gears.

This Ball Retainer O can also be used on the following internal hub gears:

- Shimano Alfine SG-S7000-8
- Shimano Alfine Di2 SG-S505
- Shimano Alfine SG-S501
- Shimano Alfine SG-S500
- Shimano Nexus SG-C6060-8C
- Shimano Nexus SG-C6060-8R/8V
- Shimano Nexus SG-C6010-8R/8V
- Shimano Nexus SG-C6000-8C
- Shimano Nexus SG-C6000-8R/8V
- Shimano Cyber Nexus SG-8C56
- Shimano Cyber Nexus SG-8C45
- Shimano Nexus SG-8C31
- Shimano Nexus SG-8C22
- Shimano Nexus SG-8C20
- Shimano Cyber Nexus SG-8R56
- Shimano Cyber Nexus SG-8R55
- Shimano Cyber Nexus SG-8R45
- Shimano Nexus SG-8R36
- Shimano Nexus SG-8R35
- Shimano Nexus SG-8R31
- Shimano Nexus SG-8R30
- Shimano Nexus SG-8R27
- Shimano Nexus SG-8R25
- Shimano Nexus SG-8R22
- Shimano Nexus SG-8R20-Belt