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2-243 B318-70 — O-RING

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

2-243 B318-70: O-RING.

The O-RING is a the manufacturer industrial component. Key specifications include material: RUBBER ISOBUTYLENE-ISOPRENE CLASS IIR, outside_diameter: 4.387 INCHES NOMINAL IN, center_hole_diameter: 4.094 INCHES MINIMUM AND 4.124 INCHES MAXIMUM IN, cross-sectional_height: 0.135 INCHES MINIMUM AND 0.143 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5331-00-579-7066, 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
2-243 B318-70
NSN: 5331-00-579-7066
FSC: 5331 — O-ring
CAGE: 02697 — PARKER-HANNIFIN CORP DIV O-RING DIVISION (USA)
SPECIFICATIONS
materialRUBBER ISOBUTYLENE-ISOPRENE CLASS IIR
outside_diameter4.387 INCHES NOMINAL IN
center_hole_diameter4.094 INCHES MINIMUM AND 4.124 INCHES MAXIMUM IN
cross-sectional_height0.135 INCHES MINIMUM AND 0.143 INCHES MAXIMUM IN
NSN5331-00-579-7066
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: 2-243 B318-70 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: 0.135 INCHES MINIMUM AND 0.143 INCHES MAXIMUM IN
•
OUTSIDE DIAMETER: 4.387 INCHES NOMINAL IN
•
CENTER HOLE DIAMETER: 4.094 INCHES MINIMUM AND 4.124 INCHES MAXIMUM IN
•
MATERIAL: RUBBER ISOBUTYLENE-ISOPRENE CLASS IIR
TECHNICAL CHARACTERISTICS
CROSS-SECTIONAL HEIGHT0.135 INCHES MINIMUM AND 0.143 INCHES MAXIMUM IN
OUTSIDE DIAMETER4.387 INCHES NOMINAL IN
CENTER HOLE DIAMETER4.094 INCHES MINIMUM AND 4.124 INCHES MAXIMUM IN
MATERIALRUBBER ISOBUTYLENE-ISOPRENE CLASS IIR
SUBSTITUTES & CROSS-REFERENCES 3
639AS6696-5Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
S847Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
ARP568-243MILG2 2050Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 2-243 B318-70?
2-243 B318-70 is a O-RING.
What parts can replace 2-243 B318-70?
There are 3 known substitutes for 2-243 B318-70: 639AS6696-5, S847, ARP568-243MILG2 2050. Substitute compatibility should be verified for your specific system.
What is the NSN for 2-243 B318-70?
2-243 B318-70 is cataloged in the U.S. Government catalog under NSN 5331-00-579-7066. 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.