Bearing Suffix Meaning
One table mapping seal, shield and clearance suffixes across naming systems: ZZ/2Z, 2RS/2RSR/DDU/LLU/EE, C3/CM. Dimension and feature naming only.
This page lists which suffix means the same physical feature across different bearing naming systems. It covers naming only — for dimensions, see the specific bearing’s own page.
Shield and seal suffixes
| Feature | Common / ISO-style | Also seen as |
|---|---|---|
| Two metal shields, non-contact, both sides | ZZ | 2Z |
| One metal shield, non-contact, one side | Z | — |
| Two rubber contact seals, both sides | 2RS | 2RSR, DDU, LLU |
| One rubber contact seal, one side | RS | RSR, DU, LU |
| No shield or seal | (none, open) | OPEN |
Clearance suffixes
| Feature | Common / ISO-style | Also seen as |
|---|---|---|
| Standard radial clearance | C0, or no suffix | CN |
| Wider than standard (common for interference fits and electric motors) | C3 | CM (motor-quality clearance on some brands, broadly similar range to C3) |
| Tighter than standard | C2 | — |
Exact clearance ranges in microns vary slightly by brand and bore size under ISO 5753-1; confirm the micron range for a specific size on the bearing clearance chart or against the buyer’s own specification sheet rather than assuming two brands’ suffixes are numerically identical.
Using this table
Match the physical feature first (shield, seal or clearance), then read across to find FULI’s suffix for that feature. See open, ZZ or 2RS seal selector for choosing a seal type, or C0 vs C3 clearance checklist for choosing a clearance class.
If a drawing calls out a suffix not listed here, send the full part number or spec sheet to sales@fuli-bearings.com and we match it to the equivalent FULI specification before quoting.
SKF, FAG, NSK and NTN are trademarks of their respective owners. FULI is not affiliated with, authorized by or endorsed by any of these companies. Suffix letters are shown for naming reference only.
FAQ
Why do different suppliers use different letters for the same seal?
Each bearing maker set its own suffix convention decades ago — SKF, FAG, NSK and NTN among others — and the industry never unified them, so the same physical feature (for example two rubber contact seals) is written 2RS, 2RSR, DDU or LLU depending on which naming system the supplier follows.
Does FULI use its own suffix system?
FULI uses the common ISO-style suffixes: ZZ for metal shields, 2RS for rubber seals, C3 for wider clearance. If a cross-reference drawing specifies another brand's suffix, use this table to find the FULI equivalent and quote by the FULI code.
Can I just send the other brand's full part number instead of converting it?
Yes — send the original number and we match the dimensions and features directly. This table is for understanding what a drawing or spec sheet calls for when you need to specify it yourself.