What do ZZ, 2Z, DDU, VV, LLU and LLB mean?
These are seal or shield codes. They describe the closure design of the bearing, while a separate suffix such as C3 describes internal clearance. Read the code in the context of its manufacturer and bearing series.
| Brand | Code | Closure meaning |
|---|---|---|
| SKF | 2Z | Shields on both sides |
| SKF | 2RSH | RSH contact seals on both sides |
| NSK | ZZ | Shields on both sides |
| NSK | DDU | Contact rubber seals on both sides |
| NSK | VV | Non-contact rubber seals on both sides |
| NTN | ZZ | Steel shields |
| NTN | LLU | Contact-type synthetic rubber seals |
| NTN | LLB | Non-contact-type synthetic rubber seals |
| NTN | LLH | Low-torque-type synthetic rubber seals |
The table explains marking meanings. A similar closure description does not establish interchangeability: the full designation, dimensions, internal design and machine requirements still belong together.
Does C3 mean sealed, and is CM the same as C3?
C3 means internal clearance greater than Normal; it does not describe a seal. CM is an electric-motor clearance designation in the NSK and NTN references covered here, and should be kept as CM when copying a requirement.
Keep closure and clearance separate
An NSK marking can include both ZZ and CM: ZZ describes shields, while CM describes the internal-clearance specification. Likewise, a closure code and C3 can appear together.
Do not choose clearance from the machine label alone
Copy the existing bearing designation and the machine's specified replacement. Calling a machine an “electric motor” is not enough to choose between Normal, C3 or CM.
After reading the suffix, use the NSK NSKHPS model table to find the published base dimensions and separate speed limits for open, ZZ/VV and DDU variants.
Other trailing characters can identify cage, precision, grease or special construction. Preserve those characters even when the base bearing size looks familiar.
How do I read a bearing marking before ordering?
- Record the manufacturer name and every line of characters on the ring.
- Keep the base model, closure suffix and clearance suffix together, including punctuation.
- Photograph both faces and the packaging label if available.
- Include quantity, the machine model and the delivery destination.
What if I only know the bore size?
Measure the bore, outside diameter and width, then send the remaining marking and photographs. A shared bore does not identify the bearing series, closure or internal-clearance requirement. Use the 6200-series size guide for that specific bearing family, or the tapered roller guide for cone-and-cup assemblies.
Send SKF, NSK or NTN bearing markings to Sardar Mill Store
Our bearing desk is at 43 Main GB Road, Delhi 110006. Send the complete marking, photos, quantity and delivery PIN code by WhatsApp, or bring the old part to the shop. For remote and wholesale orders, use one line per brand and full designation.
Brand: ___ · Full marking: ___ · Quantity: ___ · Machine: ___ · Delivery PIN: ___ · Required date: ___