Cuno filter bags live on as the 3M™ NB Series — “NB” for Nominal Bag — and the part numbers are strictly positional: micron, material, size, and collar run together in one string. Read the number off your bag or box and decode it below, or send it through the quote form and we’ll cross it.
Anatomy of an NB Series Part Number
NB numbers read: NB + micron (4 digits, zero-padded) + material (3 letters) + size + collar. Example: NB0010PPS2C = Nominal Bag, 10 micron, Polypropylene felt with polypropylene collar, size 2 (7″ × 32″), plastic Collar. A number like 70020189521 on the same box is a 3M internal stock number — it doesn’t decode; look for the NB string.
Material Codes
| NB code | Meaning | Micron grades | Universal Filters equivalent |
|---|---|---|---|
| PPS | Polypropylene felt, singed finish, polypropylene collar — the FDA food-contact option | 1–200 nominal | PG polypropylene felt, glazed, FDA grades available |
| EES | Polyester felt, polyester collar (higher temperature, not food-rated) | 1–200 nominal | PEG polyester felt, glazed, to ~275°F |
| NYS | Nylon monofilament mesh (ring top only, strap handle) | 25–1200 nominal | NMO mesh, 35–800 µm (coarser than 800 quoted by application) |
| PES | Legacy Cuno-era code: polyester media, polypropylene collar (dropped from current 3M guides) | felt range | PEG polyester felt — same cross as EES |
Size & Collar Codes
| NB code | Meaning | Universal Filters cross |
|---|---|---|
| 1 | Size #1: 7″ dia. × 17–18″ (3M’s own literature varies) | Size 1 — industry-standard #1 basket, direct interchange |
| 2 | Size #2: 7″ dia. × 32″ | Size 2 — direct interchange |
| C | Molded plastic collar (welded to the media; molded-in handle) | Snap-seal plastic flange with molded-in handles (P style) |
| R | Galvanized steel ring (for housings that won’t take the collar; standard on mesh bags) | S galvanized ring — stainless (SS) and polypropylene (SP) also available |
The NB line stops there: no size 3 or 4 (4″-diameter) bags, no stainless ring, no drawstring — we make all of those if your process needs them. NB felt bags are welded-seam construction as standard; so are our welded bags, or choose sewn and save.
The 9″ “Cuno-Style” Bags Are a Different Animal
The bags everyone calls “Cuno PC” style — the 9″-diameter ring bags for legacy Cuno PC housings — are not part of the NB numbering at all, and 3M no longer publishes literature for them. We manufacture them as a standard item: 9″ × 20″ (PC1) and 9″ × 31″ (PC2) ring-top bags in any felt or mesh media, including an oversize 9″ ring for housings where the standard ring runs small. Industry dimensions for the long PC bag vary by maker (30–31″) — tell us the housing and we’ll confirm fit before anything ships.
Worked Examples
| Cuno / 3M part number | What it is | Universal Filters equivalent |
|---|---|---|
| NB0010PPS2C | 10 µm polypropylene felt, size 2, plastic collar | PG-10, size 2, snap-seal flange |
| NB0001PPS2C | 1 µm polypropylene felt, size 2, plastic collar | PG-1, size 2, snap-seal flange |
| NB0005PPS1C | 5 µm polypropylene felt, size 1, plastic collar | PG-5, size 1, snap-seal flange |
| NB0050EES2C | 50 µm polyester felt, size 2, plastic collar | PEG-50, size 2, snap-seal flange |
| NB0005PPS2R | 5 µm polypropylene felt, size 2, steel ring | PG-5, size 2, S galvanized ring |
| NB0025NYS2R | 25 µm nylon mesh, size 2, steel ring | NMO mesh size 2, S ring, with handle |
| NB0200EES2R | 200 µm polyester felt, size 2, steel ring | PEG-200, size 2, S ring |
| NB1200NYS2R | 1200 µm nylon mesh, size 2, steel ring | Coarse mesh beyond our standard NMO 800 µm — quoted by application |
What Doesn’t Decode with This Scheme
DFG numbers (e.g., DFG001PP2R) are the DuoFLO™ / 3M™ DF Series — rigid graded-porosity elements that drop into bag housings but aren’t bags; if you’re using them we can usually quote a high-efficiency bag for the same housing. Cartridge families (Betapure™, Micro-Klean™) and Aqua-Pure™ water products are unrelated numbering. And a note on the brand: Cuno became 3M Purification in 2005, and the industrial filtration line changed hands again in 2025 — whoever’s name is on the box, the NB numbers decode the same way, and we cross them all.
Fit & Rating Notes
NB ratings are nominal by definition — that’s what the N stands for — and our felt ratings use the same nominal convention, so micron-for-micron crosses are honest ones. NB felts are singed on the outside; our glazed (G) felts match that finish. The plastic-collar bags weld the media to the collar — our flange-top bags seal the same way in the housing, and we’ll match collar material to your chemistry and temperature.
Cross a Cuno or 3M part number now: request a quote or call 800-554-8555.
3M, Cuno, DuoFLO, Betapure, Micro-Klean, and Aqua-Pure are trademarks of their respective owners. Nomenclature above is drawn from published CUNO and 3M catalog literature for identification purposes only. Universal Filters is not affiliated with 3M, Solventum, or Thermo Fisher Scientific; we manufacture compatible replacement filter bags.