PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

6125-4Valve,restrictor Check

Pneudraulics, Inc. · NSN 4820-00-574-5643 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-574-5643 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-574-5643. Primary manufacturer part number: 6125-4.
Features
  • Valve,restrictor Check — FSC 4820
  • Connection Style: GASKET SEAL (BOSS) FIRST END
  • Mounting Position: HORIZONTAL OR VERTICAL
  • Valve Operation Method: AUTOMATIC
  • Thread Quantity Per Inch: 18 FIRST END
  • Thread Direction: RIGHT-HAND FIRST END
  • Connection Type: THREADED EXTERNAL BOSS SECOND END
  • Thread Class: 3A SECOND END A
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Aluminum Alloy Overall construction
General Description

The Valve,restrictor Check, cataloged under National Stock Number 4820-00-574-5643, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Pneudraulics, Inc.. Government technical data includes 21 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 5 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4820-00-574-5643
Primary Part Number6125-4
Item NameValve,restrictor Check
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerPneudraulics, Inc.
StatusACTIVE
Connection StyleGASKET SEAL (BOSS) FIRST END
Mounting PositionHORIZONTAL OR VERTICAL
Valve Operation MethodAUTOMATIC
Thread Quantity Per Inch18 FIRST END
Thread DirectionRIGHT-HAND FIRST END
Connection TypeTHREADED EXTERNAL BOSS SECOND END
Thread Class3A SECOND END A
Nominal Outside Diameter Tube Accommodated0.375 INCHES FIRST END IN
MaterialALUMINUM ALLOY OVERALL
Operating Pressure3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
Media for Which DesignedOIL, HYDRAULIC SINGLE RESPONSE
Style DesignatorSTRAIGHT THRU
Nominal Thread Size0.562 INCHES FIRST END IN
Thread Series DesignatorUNIFIED NATIONAL JOINT FINE (UNJF) FIRST END
Thread DirectionRIGHT-HAND SECOND END
Connection StyleEXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END
Test Data Document26512-A51DCVBH027 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.).
Disk Loading MethodSPRING
Connection TypeTHREADED INTERNAL BOSS FIRST END
Thread Class3B FIRST END
Flow Control DevicePOPPET
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 5
5330-00-154-74066191 INTERCHANGEABLE
Seal,plain Encased
Skf Usa Inc. Dba Skf Aerospace Sealing Solutions
3455-00-232-4115 INTERCHANGEABLE
Reamer,machine
1680-00-439-312161254 INTERCHANGEABLE
Panel,seat Side
B E Aerospace Inc Services Div
9540-01-231-7654NAS342-26-7075-0 INTERCHANGEABLE
Angle,structural
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
4720-01-478-8976 INTERCHANGEABLE
Tubing,nonmetallic
Cross-Reference Index
Part NumberManufacturer
A51H9221-3 Northrop Grumman Systems Corporation (USA)
A51H9221-3 Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems (USA)
A51H9221-3 Northrop Grumman Systems Corporation (USA)
6125-4 PRIMARY Pneudraulics, Inc. (USA)
Related Parts
5330-00-154-7406INTERCHANGEABLE
SEAL,PLAIN ENCASED
6191
3455-00-232-4115INTERCHANGEABLE
REAMER,MACHINE
1680-00-439-3121INTERCHANGEABLE
PANEL,SEAT SIDE
61254
9540-01-231-7654INTERCHANGEABLE
ANGLE,STRUCTURAL
NAS342-26-7075-0
4720-01-478-8976INTERCHANGEABLE
TUBING,NONMETALLIC

Frequently Asked Questions

What is NSN 4820-00-574-5643?

NSN 4820-00-574-5643 is a Valve,restrictor Check, manufactured by Pneudraulics, Inc., classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-00-574-5643?

NSN 4820-00-574-5643 has 4 cross-referenced part numbers: A51H9221-3 (Northrop Grumman Systems Corporation), A51H9221-3 (Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems), A51H9221-3 (Northrop Grumman Systems Corporation), 6125-4 (Pneudraulics, Inc.).

What NSN replaces 4820-00-574-5643?

There are 5 known substitutes for 4820-00-574-5643: 5330-00-154-7406, 3455-00-232-4115, 1680-00-439-3121 and 2 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 6125-4?

Key specifications for 6125-4: Connection Style: GASKET SEAL (BOSS) FIRST END; Mounting Position: HORIZONTAL OR VERTICAL; Valve Operation Method: AUTOMATIC; Thread Quantity Per Inch: 18 FIRST END. 21 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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