The O-Ring, cataloged under National Stock Number 5331-01-561-1021, is classified within Federal Supply Class 5331 (O-ring) of the Hardware and Abrasives group. The manufacturer of record is Hii Unmanned Systems, Inc. The record lists 4 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5331-01-561-1021 |
| Primary Part Number | 25-042 |
| Item Name | O-Ring |
| FSC / FSG | 5331 / 53 — O-ring |
| Manufacturer | Hii Unmanned 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 |
|---|---|
| 25-042 | J. Bornhoft Industriegerate Gesellschaft Mit Beschrankter Haftung (DEU) |
| 25-042 PRIMARY | Hii Unmanned Systems, Inc (USA) |
| 25-042 | Leidos Australia Pty Limited (AUS) |
| 25-042 | Bluezone Group Pty Limited (AUS) |
| Reference | Meaning |
|---|---|
| 25-042 | 3/9 Design control — primary reference Hydroid, Llc |
NSN 5331-01-561-1021 is a O-Ring, manufactured by Hii Unmanned Systems, Inc, classified under FSC 5331, O-ring. Status: active.
NSN 5331-01-561-1021 has 4 manufacturer part numbers on file: 25-042 (J. Bornhoft Industriegerate Gesellschaft Mit Beschrankter Haftung), 25-042 (Hii Unmanned Systems, Inc), 25-042 (Leidos Australia Pty Limited), 25-042 (Bluezone Group Pty Limited).
1 possible match (shared part number, not a government interchangeability claim): 2610-01-563-7066. Verify interchangeability with system specifications before substitution.
Key specifications for 25-042: Special Features: BUNA N O-RING 042, SIZE: 3-1/4 INCH ID X 3-3/8 INCH OD X 1-16 INCH WIDTH IN. 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.