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JCM-17858 — COVER,PROTECTIVE,DUST AND MOISTU

✓ Government record, cited
— · ORING SEAL
PRODUCT OVERVIEW

JCM-17858: COVER,PROTECTIVE,DUST AND MOISTU.

COVER,PROTECTIVE,DUST AND MOISTU. Key specifications include open_end_inside_diameter: 3.855 INCHES NOMINAL IN, closed_end_overall_diameter: 4.000 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5340-01-486-9944, 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
JCM-17858
NSN: 5340-01-486-9944
FSC: 5340 — Hardware, Commercial
CAGE: 58905 — STRIKE WEAPONS AND UNMANNED AVIATION (USA)
SPECIFICATIONS
open_end_inside_diameter3.855 INCHES NOMINAL IN
closed_end_overall_diameter4.000 INCHES NOMINAL IN
NSN5340-01-486-9944
COMPONENT DIAGRAM
O-RING / SEAL — MATERIAL DETERMINES APPLICATION ID: — CROSS-SECTION CS: — SPECIFICATION Material: — Durometer: — Temp: — PN: JCM-17858 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
•
CLOSED END OVERALL DIAMETER: 4.000 INCHES NOMINAL IN
•
OPEN END INSIDE DIAMETER: 3.855 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
CLOSED END OVERALL DIAMETER4.000 INCHES NOMINAL IN
OPEN END INSIDE DIAMETER3.855 INCHES NOMINAL IN
SUBSTITUTES & CROSS-REFERENCES 2
092Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
92Reference document
Same NSN cross-reference
Reference document — Secondary reference
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 JCM-17858?
JCM-17858 is a COVER,PROTECTIVE,DUST AND MOISTU.
What parts can replace JCM-17858?
There are 2 known substitutes for JCM-17858: 092, 92. Substitute compatibility should be verified for your specific system.
What is the NSN for JCM-17858?
JCM-17858 is cataloged in the U.S. Government catalog under NSN 5340-01-486-9944. 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.