The Jam Nut, cataloged under National Stock Number 4220-01-231-9181, is classified within Federal Supply Class 4220 (Marine Lifesaving and Diving Equipment) of the Fire Fighting, Rescue, and Safety Equipment group. The manufacturer of record is Kirby Morgan Dive Systems Inc. The record lists 3 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4220-01-231-9181 |
| Primary Part Number | 550-050 |
| Item Name | Jam Nut |
| FSC / FSG | 4220 / 42 — Marine Lifesaving and Diving Equipment |
| Manufacturer | Kirby Morgan Dive Systems Inc |
| Status | ACTIVE |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| DE071 | Jfd Ltd (GBR) |
| 550-050 PRIMARY | Kirby Morgan Dive Systems Inc (USA) |
| DE071 | Jfd Australia Pty Ltd James Fisher Australia Pty Ltd (AUS) |
| Reference | Meaning |
|---|---|
| 18-48C | 5/9 Secondary reference Kirby Morgan Dive Systems Inc |
| 17-100C | 5/9 Secondary reference Kirby Morgan Dive Systems Inc |
| 592-6318369 | C/1 Advisory reference — outside the item-of-supply concept Zf Industrieantriebe Witten Gmbh |
NSN 4220-01-231-9181 is a Jam Nut, manufactured by Kirby Morgan Dive Systems Inc, classified under FSC 4220, Marine Lifesaving and Diving Equipment. Status: active.
NSN 4220-01-231-9181 has 3 manufacturer part numbers on file: DE071 (Jfd Ltd), 550-050 (Kirby Morgan Dive Systems Inc), DE071 (Jfd Australia Pty Ltd James Fisher Australia Pty Ltd).
2 possible matches (shared part number, not a government interchangeability claim): 5310-01-532-2895, 1730-01-680-6412. Verify interchangeability with system specifications before substitution.
Key specifications for 550-050: End Item Identification: DLA/GSA MANAGED ITEMS THAT CANNOT BE IDENTIFIED TO A SPECIFICS ARMY WEAPONS SYSTEMS/END ITEM. 0 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.