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Technical Data Sheet

MIL-H-81581/3 — CAPACITOR,ELECTRICAL

✓ Government record, cited
— · PIPE SECTION
PRODUCT OVERVIEW

MIL-H-81581/3: CAPACITOR,ELECTRICAL.

The CAPACITOR,ELECTRICAL is a the manufacturer cache protection component designed to preserve data integrity during power loss events in enterprise server and storage controller environments. Key specifications include seat_angle: 45.0 DEGREES SECOND END, thread_class: 3B SECOND END, connection_type: THREADED INTERNAL TUBE FIRST END, inside_diameter: 0.562 INCHES NOMINAL IN, connection_style: SWIVEL NUT FLARE FIRST END, outside_diameter: 0.688 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 4720-00-021-1019, 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
MIL-H-81581/3
NSN: 4720-00-021-1019
NIINs: 000211019, 000234216, 009991936, 009991938, 011395479, 011404381, 011412928
FSC: 4720 — Hose and Flexible Tubing
CAGE: 81349 — MILITARY SPECIFICATIONS PROMULGATED BY MILITARY DEPARTMENTS/AGENCIES UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
seat_angle45.0 DEGREES SECOND END
thread_class3B SECOND END
connection_typeTHREADED INTERNAL TUBE FIRST END
inside_diameter0.562 INCHES NOMINAL IN
connection_styleSWIVEL NUT FLARE FIRST END
outside_diameter0.688 INCHES NOMINAL IN
thread_directionRIGHT-HAND SECOND END
operating_pressure120.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM LBS
nominal_thread_size0.312 INCHES FIRST END IN
end_connection_designSTRAIGHT FIRST END
inside_surface_conditionSMOOTH
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) FIRST END
NSN4720-00-021-1019
COMPONENT DIAGRAM
PIPE SECTION — SCHEDULE = WALL THICKNESS WALL: — OD: — LENGTH: — — — PN: MIL-H-81581/3 · OEM ⚠ VERIFY BEFORE ORDERING Schedule = wall thickness, NOT pipe diameter. Sch 40 and Sch 80 have the same OD but different wall thickness. Nominal pipe size ≠ actual OD — a 1" pipe is actually 1.315" OD ✓ BROKER TIP Sch 40 = standard wall, Sch 80 = heavy wall (higher pressure), Sch 160 = extra heavy. Seamless pipe is required for high-pressure applications — welded pipe has lower ratings PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
HOSE WEIGHT: 0.100 OUNCES PER LINEAR FOOT OZ
•
FSC APPLICATION DATA: ACFT OXYGEN BREATHING SYSTEM
•
MEASURING METHOD AND LENGTH: 36.000 INCHES NOMINAL OVERALL IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-A-8625,TYPE 2 MIL SPEC SINGLE TREATMENT RESPONSE FIRST END COUPLING
•
CONNECTION TYPE: COUPLING FIRST END
•
COUPLING STYLE: THREADED INTERNAL FIRST END
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-225/6,ALLOY 2024,T4 FED SPEC SINGLE MATERIAL RESPONSE FIRST END COUPLING
•
CROSS-SECTIONAL SHAPE STYLE: ROUND
TYPICAL APPLICATIONS
  • RAID cache protection during power loss events
  • Write-back cache enablement for storage controllers
  • Enterprise server data integrity assurance
  • Hot-swap battery/capacitor replacement in production
TECHNICAL CHARACTERISTICS
HOSE WEIGHT0.100 OUNCES PER LINEAR FOOT OZ
FSC APPLICATION DATAACFT OXYGEN BREATHING SYSTEM
MEASURING METHOD AND LENGTH36.000 INCHES NOMINAL OVERALL IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-A-8625,TYPE 2 MIL SPEC SINGLE TREATMENT RESPONSE FIRST END COUPLING
CONNECTION TYPECOUPLING FIRST END
COUPLING STYLETHREADED INTERNAL FIRST END
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-225/6,ALLOY 2024,T4 FED SPEC SINGLE MATERIAL RESPONSE FIRST END COUPLING
CROSS-SECTIONAL SHAPE STYLEROUND
WALL THICKNESS0.188 INCHES NOMINAL IN
OPERATING PRESSURE70.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM LBS
SUBSTITUTES & CROSS-REFERENCES 1
REDAR 17S-1-36 CReference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MIL-H-81581/3?
MIL-H-81581/3 is a CAPACITOR,ELECTRICAL.
What parts can replace MIL-H-81581/3?
There is 1 known substitute for MIL-H-81581/3: REDAR 17S-1-36 C. Substitute compatibility should be verified for your specific system.
What is the NSN for MIL-H-81581/3?
MIL-H-81581/3 is cataloged in the U.S. Government catalog under NSN 4720-00-021-1019. 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.