ZZ (metal shielded) and 2RS (rubber sealed) are the two most common bearing closure types for replacement orders.
ZZ (Metal Shielded)
- Two metal shields, one on each side, pressed into the outer ring.
- Non-contact design — the shield does not touch the inner ring.
- Protects against dust and larger particles.
- Lower friction, higher speed capability than 2RS.
- Cannot be regreased without removing the shields.
- Best for: clean environments, high-speed motors, fans.
2RS (Rubber Sealed)
- Two rubber seals with a lip that contacts the inner ring.
- Excellent protection against moisture, fine dust, and washdown.
- Slightly higher friction than ZZ (contact seal).
- Better grease retention.
- Best for: dirty or wet environments, conveyors, agricultural equipment, pumps.
Which to order
| Your environment | Choose |
|---|---|
| Clean, indoor, moderate speed | ZZ |
| Dusty, outdoor, washdown area | 2RS |
| High speed, clean | ZZ (lower friction) |
| Motor replacement (standard) | ZZ is factory common; 2RS offers longer life |
| Don’t know | 2RS (more forgiving across conditions) |
If the original bearing suffix is unclear, 2RS is the safer MRO default. It tolerates a wider range of environments.