PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

NAS4121-370BHeat Sink,electrical-Electronic

National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use · NSN 5999-01-384-2619 · FSC 5999 · No Item Name Available
Verified by PartsTable
NSN 5999-01-384-2619 — this item is cataloged by the U.S. Government under National Stock Number 5999-01-384-2619. Primary manufacturer part number: NAS4121-370B.
Features
  • Heat Sink,electrical-Electronic — FSC 5999
  • Test Data Document: MIL-H-87111JAMIL-H-87111/5 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.).
  • Surface Treatment Document and Classification: MIL-A-8625 TYPE1 OR 2 MIL SPEC SINGLE TREATMENT RESPONSE
  • Accommodated Device Mounting Hole Quantity: 1
  • Material: ALUMINUM ALLOY
  • Mounting Facility Type and Quantity: 1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
  • Surface Treatment: ANODIZE
  • Specification/standard Data: 81349-MIL-H-87111 GOVERNMENT SPECIFICATION AND 81349-MIL-H-87111/5 GOVERNMENT SPECIFICATION
Applications
  • Applications requiring Aluminum Alloy construction
General Description

The Heat Sink,electrical-Electronic, cataloged under National Stock Number 5999-01-384-2619, is classified within Federal Supply Class 5999 (No Item Name Available) of the Electrical and Electronic Equipment Components group. The primary manufacturer of record is National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use. Government technical data includes 22 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. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active. Unit of issue: EA.

Technical Specifications
ParameterValue
NSN5999-01-384-2619
Primary Part NumberNAS4121-370B
Item NameHeat Sink,electrical-Electronic
FSC / FSG5999 / 59 — No Item Name Available
ManufacturerNational Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
StatusACTIVE
Test Data DocumentMIL-H-87111JAMIL-H-87111/5 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.).
Surface Treatment Document and ClassificationMIL-A-8625 TYPE1 OR 2 MIL SPEC SINGLE TREATMENT RESPONSE
Accommodated Device Mounting Hole Quantity1
MaterialALUMINUM ALLOY
Mounting Facility Type and Quantity1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Surface TreatmentANODIZE
Specification/standard Data81349-MIL-H-87111 GOVERNMENT SPECIFICATION AND 81349-MIL-H-87111/5 GOVERNMENT SPECIFICATION
Material Document and ClassificationMIL-H-87111 MIL SPEC SINGLE MATERIAL RESPONSE AND MIL-H-87111/5B MIL SPEC SINGLE MATERIAL RESPONSE
Unthreaded Mounting Hole Diameter0.139 INCHES MINIMUM AND 0.161 INCHES MAXIMUM SINGLE MOUNTING FACILITY IN
Body StyleHORIZONTALLY MOUNTED
Operating Power Dissipating Rating in Watts5.00
Test Data DocumentMIL-H-87111JAMIL-H-87111/5 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.).
Surface Treatment Document and ClassificationMIL-A-8625 TYPE1 OR 2 MIL SPEC SINGLE TREATMENT RESPONSE
Accommodated Device Mounting Hole Quantity1
MaterialALUMINUM ALLOY
Mounting Facility Type and Quantity1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Surface TreatmentANODIZE
Specification/standard Data81349-MIL-H-87111 GOVERNMENT SPECIFICATION AND 81349-MIL-H-87111/5 GOVERNMENT SPECIFICATION
Material Document and ClassificationMIL-H-87111 MIL SPEC SINGLE MATERIAL RESPONSE AND MIL-H-87111/5B MIL SPEC SINGLE MATERIAL RESPONSE
Unthreaded Mounting Hole Diameter0.139 INCHES MINIMUM AND 0.161 INCHES MAXIMUM SINGLE MOUNTING FACILITY IN
Body StyleHORIZONTALLY MOUNTED
Operating Power Dissipating Rating in Watts5.00
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Shelf Life Code0
Criticality CodeN
Unit of IssueEA
SMR CodeJN
Verified Substitutes 12
5999-01-395-2474NAS4117C51 SUCCESSOR
Heat Sink-Insulator
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-105-4991 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5999-01-183-9737NAS4121-016B INTERCHANGEABLE
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-202-9730 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5999-01-202-9731 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5999-01-203-6128 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5999-01-203-6130 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5999-01-204-3731 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5999-01-209-0650NAS4121-017B INTERCHANGEABLE
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-286-7295NAS4121-291B INTERCHANGEABLE
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
Cross-Reference Index
Part NumberManufacturer
MIL-H-87111 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
NAS4121 National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use (USA)
M87111/05-1A370 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
NAS4121-370B PRIMARY National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use (USA)
Related Parts
5999-01-395-2474SUCCESSOR
HEAT SINK-INSULATOR
NAS4117C51
5999-01-105-4991INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-183-9737INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4121-016B
5999-01-202-9730INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-202-9731INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-203-6128INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-203-6130INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-204-3731INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-209-0650INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4121-017B
5999-01-286-7295INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4121-291B
5999-01-395-3752INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5999-01-399-3230INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC

Frequently Asked Questions

What is NSN 5999-01-384-2619?

NSN 5999-01-384-2619 is a Heat Sink,electrical-Electronic, manufactured by National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use, classified under FSC 5999 (No Item Name Available). Status: active.

What are the part numbers for NSN 5999-01-384-2619?

NSN 5999-01-384-2619 has 4 cross-referenced part numbers: MIL-H-87111 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), NAS4121 (National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use), M87111/05-1A370 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), NAS4121-370B (National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use).

What NSN replaces 5999-01-384-2619?

There are 12 known substitutes for 5999-01-384-2619: 5999-01-395-2474, 5999-01-105-4991, 5999-01-183-9737 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of NAS4121-370B?

Key specifications for NAS4121-370B: Overall Length: 0.739 INCHES MINIMUM AND 0.761 INCHES MAXIMUM IN; Test Data Document: MIL-H-87111JAMIL-H-87111/5 SPECIFICATION (INCLUDES ENGINEERING TYPE BULLETINS, BROCHURES,ETC., THAT REFLECT SPECIFICATION TYPE DATA IN SPECIFICATION FORMAT; EXCLUDES COMMERCIAL CATALOGS, INDUSTRY DIRECTORIES, AND SIMILAR TRADE PUBLICATIONS, REFLECTING GENERAL TYPE DATA ON CERTAIN ENVIRONMENTAL AND PERFORMANCE REQUIREMENTS AND TEST CONDITIONS THAT ARE SHOWN AS "TYPICAL", "AVERAGE", "NOMINAL", ETC.).; Surface Treatment Document and Classification: MIL-A-8625 TYPE1 OR 2 MIL SPEC SINGLE TREATMENT RESPONSE; Accommodated Device Mounting Hole Quantity: 1. 28 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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