The Reducer,tube, cataloged under National Stock Number 4730-00-555-1981, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney. Government technical data includes 14 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4730-00-555-1981 |
| Primary Part Number | 261439 |
| Item Name | Reducer,tube |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney |
| Status | ACTIVE |
| Connection Style | FLARED (TUBE) FIRST END |
| Connection Style | SOCKET W/ FLARE (TUBE) SECOND END |
| Nominal Overall Length | 1.045 INCHES IN |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Connection Type | UNTHREADED INTERNAL TUBE SECOND END |
| Nominal Outside Diameter Tube Accommodated | 0.375 INCHES FIRST END IN |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES SECOND END IN |
| Nominal Thread Size | 0.375 INCHES FIRST END IN |
| Seat Angle | 37.0 DEGREES FIRST END |
| Thread Class | 2A FIRST END A |
| Thread Quantity Per Inch | 24 FIRST END |
| Material | STEEL CORROSION RESISTING OVERALL |
| Thread Series Designator | UNS FIRST END |
| Reducer Type | CONCENTRIC |
| 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 |
|---|---|
| 261439 PRIMARY | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney (USA) |
| Reference | Meaning |
|---|---|
| 261439 | 5/9 Secondary reference Turbo Power & Marine System Inc Sub of United Technologies Corp |
NSN 4730-00-555-1981 is a Reducer,tube, manufactured by Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-555-1981 has 1 manufacturer part number on file: 261439 (Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney).
1 possible match (shared part number, not a government interchangeability claim): 5315-01-478-5072. Verify interchangeability with system specifications before substitution.
Key specifications for 261439: Connection Style: FLARED (TUBE) FIRST END; Connection Style: SOCKET W/ FLARE (TUBE) SECOND END; Nominal Overall Length: 1.045 INCHES IN; Connection Type: THREADED EXTERNAL TUBE FIRST END. 14 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.