The Restrictor,fluid Flow, cataloged under National Stock Number 4730-00-421-3231, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. Government technical data includes 18 specifications, cited from the U.S. Government catalog. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 4 items share a part number with this NSN in the catalog (possible match — not a government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 | 4730-00-421-3231 |
| Item Name | Restrictor,fluid Flow |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Status | ACTIVE |
| Length | 3.375 INCHES NOMINAL IN |
| Thread Provision | THREADED LOCATION NOT OTHERWISE SPECIFIED |
| Design Type | TUBULAR, HEX SHAPE |
| Thread Series | UNF SECOND PROVISION |
| Thread Series | UNF FIRST PROVISION |
| Thread Length | 0.469 INCHES NOMINAL FIRST PROVISION IN |
| Thread Length | 0.469 INCHES NOMINAL SECOND PROVISION IN |
| Hose/tube Size for Which Designed | 318 IN. TUBE OD IN |
| Outside Diameter | 1.375 INCHES NOMINAL IN |
| Thread Direction | RIGHT-HAND FIRST PROVISION |
| Thread Direction | RIGHT-HAND SECOND PROVISION |
| Thread Size Designator | 9/16-18 SECOND PROVISION |
| Thread Size Designator | 9/16-18 FIRST PROVISION |
| Surface Treatment | PASSIVATE |
| Thread Class | 3B FIRST PROVISION |
| Thread Class | 3B SECOND PROVISION |
| Material | STEEL CORROSION RESISTING |
| Orifice Diameter | 0.297 INCHES NOMINAL IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| Q642-05-1-0 | 5/9 Secondary reference U.S. Government activity |
| Q642-05-1.0 | 3/2 Design control — primary reference U.S. Government activity |
| 2312620 | 7/9 Vendor item drawing reference Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier |
| R121W6-1.0 | 5/9 Secondary reference Transdigm Inc Div Adelwiggins Group |
| 2312620-3 | 3/9 Design control — primary reference Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier |
NSN 4730-00-421-3231 is a Restrictor,fluid Flow, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
4 possible matches (shared part number, not a government interchangeability claim): 4730-01-096-3469, 4730-01-192-8504, 4730-01-192-8505. Verify interchangeability with system specifications before substitution.
Key specifications for 4730-00-421-3231: Length: 3.375 INCHES NOMINAL IN; Thread Provision: THREADED LOCATION NOT OTHERWISE SPECIFIED; Design Type: TUBULAR, HEX SHAPE; Thread Series: UNF SECOND PROVISION. 18 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.