The O-Ring, cataloged under National Stock Number 5331-01-256-0427, is classified within Federal Supply Class 5331 (O-ring) of the Hardware and Abrasives group. The manufacturer of record is Curtiss-Wright Flow Control Service, Llc Dba Engineered Arresting Systems - Esco Div Cw Flow Control Svc Llc Dba. Government technical data includes 2 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5331-01-256-0427 |
| Primary Part Number | 04521-020 |
| Item Name | O-Ring |
| FSC / FSG | 5331 / 53 — O-ring |
| Manufacturer | Curtiss-Wright Flow Control Service, Llc Dba Engineered Arresting Systems - Esco Div Cw Flow Control Svc Llc Dba |
| Status | ACTIVE |
| Cross-Sectional Height | 0.135 INCHES MINIMUM AND 0.143 INCHES MAXIMUM IN |
| Center Hole Diameter | 2.589 INCHES MINIMUM AND 2.629 INCHES MAXIMUM IN |
| 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 |
|---|---|
| 52-D-6012-8 | Defence Liaison Services Pty Ltd (AUS) |
| 04521-020 | Defence Liaison Services Pty Ltd (AUS) |
| 04521-020 PRIMARY | Curtiss-Wright Flow Control Service, Llc Dba Engineered Arresting Systems - Esco Div Cw Flow Control Svc Llc Dba (USA) |
| Reference | Meaning |
|---|---|
| 2-231 | C/1 Advisory reference — outside the item-of-supply concept Zf Industrieantriebe Witten Gmbh |
| 52-D-6012-8 | 5/9 Secondary reference Curtiss-Wright Flow Control Service, Llc Dba Engineered Arresting Systems - Esco Div Cw Flow Control Svc Llc Dba |
NSN 5331-01-256-0427 is a O-Ring, manufactured by Curtiss-Wright Flow Control Service, Llc Dba Engineered Arresting Systems - Esco Div Cw Flow Control Svc Llc Dba, classified under FSC 5331, O-ring. Status: active.
NSN 5331-01-256-0427 has 3 manufacturer part numbers on file: 52-D-6012-8 (Defence Liaison Services Pty Ltd), 04521-020 (Defence Liaison Services Pty Ltd), 04521-020 (Curtiss-Wright Flow Control Service, Llc Dba Engineered Arresting Systems - Esco Div Cw Flow Control Svc Llc Dba).
Key specifications for 04521-020: Cross-Sectional Height: 0.135 INCHES MINIMUM AND 0.143 INCHES MAXIMUM IN; Center Hole Diameter: 2.589 INCHES MINIMUM AND 2.629 INCHES MAXIMUM IN. 2 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.