PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

635-1.25B2Heat Sink,electrical-Electronic

Eg and G Wakefield Engineering · NSN 5999-01-212-1101 · FSC 5999 · No Item Name Available
Verified by PartsTable
NSN 5999-01-212-1101 — this item is cataloged by the U.S. Government under National Stock Number 5999-01-212-1101. Primary manufacturer part number: 635-1.25B2.
Features
  • Heat Sink,electrical-Electronic — FSC 5999
  • Overall Diameter: 0.500 INCHES NOMINAL IN
  • Test Data Document: 81349-MIL-H-87111 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.).
  • Nuclear Hardness Critical Feature: HARDENED
  • Material Document and Classification: QQ-C-533 FED SPEC SINGLE MATERIAL RESPONSE OR MIL-C-81021 MIL SPEC SINGLE MATERIAL RESPONSE
  • Unthreaded Mounting Hole Diameter: 0.318 INCHES NOMINAL SECOND MOUNTING FACILITY IN
  • Surface Treatment Document and Classification: MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE
  • Surface Treatment: ANODIZE
Applications
  • Applications requiring Copper Alloy construction
General Description

The Heat Sink,electrical-Electronic, cataloged under National Stock Number 5999-01-212-1101, 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 Eg and G Wakefield Engineering. Government technical data includes 20 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 9 commercial cross-references from 7 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled. Unit of issue: EA.

Technical Specifications
ParameterValue
NSN5999-01-212-1101
Primary Part Number635-1.25B2
Item NameHeat Sink,electrical-Electronic
FSC / FSG5999 / 59 — No Item Name Available
ManufacturerEg and G Wakefield Engineering
StatusCANCELLED
Overall Diameter0.500 INCHES NOMINAL IN
Test Data Document81349-MIL-H-87111 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.).
Nuclear Hardness Critical FeatureHARDENED
Material Document and ClassificationQQ-C-533 FED SPEC SINGLE MATERIAL RESPONSE OR MIL-C-81021 MIL SPEC SINGLE MATERIAL RESPONSE
Unthreaded Mounting Hole Diameter0.318 INCHES NOMINAL SECOND MOUNTING FACILITY IN
Surface Treatment Document and ClassificationMIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE
Surface TreatmentANODIZE
Specification/standard Data81349-MIL-H-87111/3 GOVERNMENT SPECIFICATION
MaterialCOPPER ALLOY
Mounting Facility Type and Quantity1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Overall Diameter0.500 INCHES NOMINAL IN
Test Data Document81349-MIL-H-87111 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.).
Nuclear Hardness Critical FeatureHARDENED
Material Document and ClassificationQQ-C-533 FED SPEC SINGLE MATERIAL RESPONSE OR MIL-C-81021 MIL SPEC SINGLE MATERIAL RESPONSE
Unthreaded Mounting Hole Diameter0.318 INCHES NOMINAL SECOND MOUNTING FACILITY IN
Surface Treatment Document and ClassificationMIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE
Surface TreatmentANODIZE
Specification/standard Data81349-MIL-H-87111/3 GOVERNMENT SPECIFICATION
MaterialCOPPER ALLOY
Mounting Facility Type and Quantity1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Lifecycle & Compliance
Acquisition StatusCANCELLED
Successor5999-01-360-1469 (KLG365D)
HAZMATNo
Shelf Life Code0
Criticality CodeQ
Unit of IssueEA
SMR CodeZN
Weight0.0100 lbs
Cube0.0001 cu ft
Verified Substitutes 12
No Item Name Available
5999-01-360-1469KLG365D SUCCESSOR
Heat Sink,electrical-Electronic
Eaton Aerospace Llc Dba Eaton Inoac Div Fluid & Electrical Distribution
5999-01-089-1006207SB SUCCESSOR
Heat Sink,electrical-Electronic
Eg and G Inc
5999-01-117-8507NAS4119E07C SUCCESSOR
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-152-5202NAS4119E07H SUCCESSOR
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-170-8149NAS4119E03B SUCCESSOR
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-211-6669NAS4119E03C SUCCESSOR
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-211-6671NAS4119E04C SUCCESSOR
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-211-7886NAS4119E05C SUCCESSOR
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5999-01-216-2398NAS4119E09B SUCCESSOR
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
635-1.25B2 Eg and G Wakefield Engineering (USA)
1438M42P01 General Electric Co (USA)
10139607 Nimikkeistokeskus Ncb Finland (FIN)
MODEL 444 Aham Plastics (USA)
M87111/03-1A16 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
MIL-H-87111/3 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
5016B Aavid Thermalloy Llc (USA)
SG00-0635 Raven Electronics Corp (USA)
MODEL 316-B Aham Plastics (USA)
Related Parts
SUCCESSOR 5999-01-360-1469 Heat Sink,electrical-Electronic · KLG365D
5999-01-091-4821SUCCESSOR
NO ITEM NAME AVAILABLE
5999-01-089-1006SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
207SB
5999-01-117-8507SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E07C
5999-01-152-5202SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E07H
5999-01-170-8149SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E03B
5999-01-211-6669SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E03C
5999-01-211-6671SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E04C
5999-01-211-7886SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E05C
5999-01-216-2398SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E09B
5999-01-224-6300SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119A14B
5999-01-247-6075SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119A18H

Frequently Asked Questions

What is NSN 5999-01-212-1101?

NSN 5999-01-212-1101 is a Heat Sink,electrical-Electronic, manufactured by Eg and G Wakefield Engineering, classified under FSC 5999 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 5999-01-212-1101?

NSN 5999-01-212-1101 has 9 cross-referenced part numbers: 635-1.25B2 (Eg and G Wakefield Engineering), 1438M42P01 (General Electric Co), 10139607 (Nimikkeistokeskus Ncb Finland), MODEL 444 (Aham Plastics), M87111/03-1A16 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M) and 4 more.

What NSN replaces 5999-01-212-1101?

There are 12 known substitutes for 5999-01-212-1101: 5999-01-091-4821, 5999-01-360-1469, 5999-01-089-1006 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 635-1.25B2?

Key specifications for 635-1.25B2: Overall Height: 0.250 INCHES NOMINAL IN; Overall Diameter: 0.500 INCHES NOMINAL IN; Special Features: NUCLEAR HARDNESS CRITICAL ITEMS; Test Data Document: 81349-MIL-H-87111 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.).. 24 total characteristics are documented in the Federal Logistics Information System.

Is NSN 5999-01-212-1101 still in active supply?

NSN 5999-01-212-1101 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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