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ST7M251-10 — O-RING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

ST7M251-10: O-RING.

The O-RING is a the manufacturer industrial component. Key specifications include material: RUBBER FLUOROSILICONE CLASS FQ, hardness_rating: 70.0 SHORE DUROMETER A NOMINAL, center_hole_diameter: 0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN, elongation_percentage: 125 MAXIMUM, cross-sectional_height: 0.033 INCHES MINIMUM AND 0.037 INCHES MAXIMUM IN, material_document_and_classification: MIL-R-25988 TYPE 1, CLASS 1, GRADE 70 MIL SPEC SINGLE MATERIAL RESPONSE. This part is cataloged in the U.S.

Government catalog under NSN 5331-00-324-7731, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
ST7M251-10
NSN: 5331-00-324-7731
FSC: 5331 — O-ring
CAGE: 76301 — THE BOEING COMPANY DIV DEFENSE (USA)
SPECIFICATIONS
materialRUBBER FLUOROSILICONE CLASS FQ
hardness_rating70.0 SHORE DUROMETER A NOMINAL
center_hole_diameter0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN
elongation_percentage125 MAXIMUM
cross-sectional_height0.033 INCHES MINIMUM AND 0.037 INCHES MAXIMUM IN
end_item_identificationW/S: AIRCRAFT, EAGLE F-15; AIRCRAFT, HARRIER AV-8B; F/A-18E/F HORNET AIRCRAFT; AIRCRAFT, STRATOFORTRESS B-52; AIRCRAFT, HORNET F/A-18
material_document_and_classificationMIL-R-25988 TYPE 1, CLASS 1, GRADE 70 MIL SPEC SINGLE MATERIAL RESPONSE
NSN5331-00-324-7731
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: ST7M251-10 MFR: OEM ⚠ VERIFY BEFORE ORDERING Wrong material = failure. Viton for oil/fuel, EPDM for water/steam, Buna-N for general purpose, Silicone for food-grade. Chemical incompatibility causes swelling, brittleness, or rapid degradation ✓ BROKER TIP Durometer (hardness) affects sealing pressure tolerance. Higher Shore A = harder = higher pressure. Standard durometer is 70A — verify if application requires different hardness PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
CROSS-SECTIONAL HEIGHT: 0.033 INCHES MINIMUM AND 0.037 INCHES MAXIMUM IN
•
HARDNESS RATING: 70.0 SHORE DUROMETER A NOMINAL
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-R-25988 TYPE 1, CLASS 1, GRADE 70 MIL SPEC SINGLE MATERIAL RESPONSE
•
ELONGATION PERCENTAGE: 125 MAXIMUM
•
CENTER HOLE DIAMETER: 0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN
•
MATERIAL: RUBBER FLUOROSILICONE CLASS FQ
TECHNICAL CHARACTERISTICS
CROSS-SECTIONAL HEIGHT0.033 INCHES MINIMUM AND 0.037 INCHES MAXIMUM IN
HARDNESS RATING70.0 SHORE DUROMETER A NOMINAL
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-R-25988 TYPE 1, CLASS 1, GRADE 70 MIL SPEC SINGLE MATERIAL RESPONSE
ELONGATION PERCENTAGE125 MAXIMUM
CENTER HOLE DIAMETER0.296 INCHES MINIMUM AND 0.306 INCHES MAXIMUM IN
END ITEM IDENTIFICATIONW/S: AIRCRAFT, EAGLE F-15; AIRCRAFT, HARRIER AV-8B; F/A-18E/F HORNET AIRCRAFT; AIRCRAFT, STRATOFORTRESS B-52; AIRCRAFT, HORNET F/A-18
MATERIALRUBBER FLUOROSILICONE CLASS FQ
OTHER ITEMS IN FSC 5331 — O-ring
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5331-00-001-1971 5331-00-001-1979 5331-00-001-3904 5331-00-001-3905 5331-00-001-3906 5331-00-001-3908 5331-00-001-3923 5331-00-001-3924
SUBSTITUTES & CROSS-REFERENCES 7
10163281Reference document
Same NSN cross-reference
Reference document — Informative reference only
SZ7583-10Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
CGR1601-0125-10Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
00301-035F70Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
MIL-R-25988Reference document
Same NSN cross-reference
Reference document — Identification reference
1966-017ASame NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is ST7M251-10?
ST7M251-10 is a O-RING.
What parts can replace ST7M251-10?
There are 7 known substitutes for ST7M251-10: 10163281, SZ7583-10, CGR1601-0125-10 and 4 more. Substitute compatibility should be verified for your specific system.
What is the NSN for ST7M251-10?
ST7M251-10 is cataloged in the U.S. Government catalog under NSN 5331-00-324-7731. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.