PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MIL-DTL-25988/1O-Ring

Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M · NSN 5331-01-125-6269 · FSC 5331 · O-Ring
Verified by PartsTable
NSN 5331-01-125-6269 — this item is cataloged by the U.S. Government under National Stock Number 5331-01-125-6269. Primary manufacturer part number: MIL-DTL-25988/1.
Features
  • O-Ring — FSC 5331
  • Cross-Sectional Height: 0.205 INCHES MINIMUM AND 0.215 INCHES MAXIMUM IN
  • Center Hole Diameter: 4.195 INCHES MINIMUM AND 4.255 INCHES MAXIMUM IN
  • Outside Diameter: 4.645 INCHES NOMINAL IN
  • Material: RUBBER FLUOROSILICONE CLASS FQ
  • Elongation Percentage: 125 MAXIMUM
  • Hardness Rating: 70.0 SHORE DUROMETER A NOMINAL
  • 4 verified cross-references
Applications
  • Fluid containment and leak prevention
  • Pressure boundary maintenance
  • Environmental sealing
  • Applications requiring Rubber Fluorosilicone Class Fq construction
General Description

The O-Ring, cataloged under National Stock Number 5331-01-125-6269, is classified within Federal Supply Class 5331 (O-Ring) of the Hardware and Abrasives group. The primary manufacturer of record is Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M. Government technical data includes 6 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 1 verified substitute exists in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5331-01-125-6269
Primary Part NumberMIL-DTL-25988/1
Item NameO-Ring
FSC / FSG5331 / 53 — O-Ring
ManufacturerMilitary Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
StatusACTIVE
Cross-Sectional Height0.205 INCHES MINIMUM AND 0.215 INCHES MAXIMUM IN
Center Hole Diameter4.195 INCHES MINIMUM AND 4.255 INCHES MAXIMUM IN
Outside Diameter4.645 INCHES NOMINAL IN
MaterialRUBBER FLUOROSILICONE CLASS FQ
Elongation Percentage125 MAXIMUM
Hardness Rating70.0 SHORE DUROMETER A NOMINAL
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 1
4730-00-803-2007145F-4-4 INTERCHANGEABLE
Tee,pipe to Tube
Staver Hydraulics Co., Inc. Dba Lehigh Gasket
Cross-Reference Index
Part NumberManufacturer
MIL-DTL-25988/1 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
MIL-R-25988/1 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
M25988/1-347 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
10163404 Nimikkeistokeskus Ncb Finland (FIN)
Related Parts
4730-00-803-2007INTERCHANGEABLE
TEE,PIPE TO TUBE
145F-4-4

Frequently Asked Questions

What is NSN 5331-01-125-6269?

NSN 5331-01-125-6269 is a O-Ring, manufactured by Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M, classified under FSC 5331 (O-Ring). Status: active.

What are the part numbers for NSN 5331-01-125-6269?

NSN 5331-01-125-6269 has 4 cross-referenced part numbers: MIL-DTL-25988/1 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), MIL-R-25988/1 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), M25988/1-347 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), 10163404 (Nimikkeistokeskus Ncb Finland).

What NSN replaces 5331-01-125-6269?

There is 1 known substitute for 5331-01-125-6269: 4730-00-803-2007. Verify interchangeability with system specifications before substitution.

What are the specifications of MIL-DTL-25988/1?

Key specifications for MIL-DTL-25988/1: Cross-Sectional Height: 0.205 INCHES MINIMUM AND 0.215 INCHES MAXIMUM IN; Center Hole Diameter: 4.195 INCHES MINIMUM AND 4.255 INCHES MAXIMUM IN; Outside Diameter: 4.645 INCHES NOMINAL IN; Material: RUBBER FLUOROSILICONE CLASS FQ. 6 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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