The Valve,restrictor Check, cataloged under National Stock Number 4820-01-159-4523, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Pneudraulics, Inc.. Government technical data includes 19 specifications, cited from the U.S. Government catalog. The record lists 2 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-159-4523 |
| Primary Part Number | 6125-8 |
| Item Name | Valve,restrictor Check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Pneudraulics, Inc. |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END |
| Connection Style | GASKET SEAL (BOSS) FIRST END |
| Mounting Position | HORIZONTAL |
| Criticality Code Justification | FEAT |
| Connection Type | THREADED INTERNAL BOSS FIRST END |
| Connection Type | THREADED EXTERNAL BOSS SECOND END |
| Style Designator | STRAIGHT THRU |
| Aperture Diameter | 0.030 INCHES NOMINAL IN |
| Thread Direction | RIGHT-HAND SECOND END |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.562 INCHES SECOND END IN |
| Nominal Thread Size | 0.562 INCHES FIRST END IN |
| Thread Class | 3A SECOND END A |
| Thread Class | 3B FIRST END |
| Thread Quantity Per Inch | 18 FIRST END |
| Material | ALUMINUM ALLOY OVERALL |
| Thread Series Designator | UNJS SECOND END |
| Valve Operation Method | AUTOMATIC |
| 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 |
|---|---|
| 6125-8 PRIMARY | Pneudraulics, Inc. (USA) |
| A51H9221-5 | Northrop Grumman Systems Corporation (USA) |
| Reference | Meaning |
|---|---|
| A51H9221-5 | 5/9 Secondary reference Northrop Grumman Systems Corporation |
| A51H9221-5 | 5/9 Secondary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems |
NSN 4820-01-159-4523 is a Valve,restrictor Check, manufactured by Pneudraulics, Inc., classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-159-4523 has 2 manufacturer part numbers on file: 6125-8 (Pneudraulics, Inc.), A51H9221-5 (Northrop Grumman Systems Corporation).
2 possible matches (shared part number, not a government interchangeability claim): 4720-01-238-0970, 5330-01-300-8610. Verify interchangeability with system specifications before substitution.
Key specifications for 6125-8: Flow Control Device: POPPET; Connection Style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END; Connection Style: GASKET SEAL (BOSS) FIRST END; Mounting Position: HORIZONTAL. 19 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.