PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

C42121Z21C4Heat Sink,electrical-Electronic

Hensoldt Sensors Gmbh · NSN 5999-01-033-5474 · FSC 5999 · No Item Name Available
Verified by PartsTable
NSN 5999-01-033-5474 — this item is cataloged by the U.S. Government under National Stock Number 5999-01-033-5474. Primary manufacturer part number: C42121Z21C4.
Features
  • Heat Sink,electrical-Electronic — FSC 5999
  • Material: COPPER ALLOY
  • Surface Treatment Document and Classification: MIL-F-495 MIL SPEC SINGLE TREATMENT RESPONSE
  • Mounting Facility Type and Quantity: 1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
  • Unthreaded Mounting Hole Diameter: 0.240 INCHES MINIMUM AND 0.265 INCHES MAXIMUM SINGLE MOUNTING FACILITY IN
  • Material Document and Classification: MIL-C-81021 MIL SPEC SINGLE MATERIAL RESPONSE
  • Surface Treatment: OXIDE
  • Overall Diameter: 0.275 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN
Applications
  • Applications requiring Copper Alloy construction
General Description

The Heat Sink,electrical-Electronic, cataloged under National Stock Number 5999-01-033-5474, 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 Hensoldt Sensors Gmbh. Government technical data includes 14 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 9 commercial cross-references from 8 manufacturers, enabling identification through both NSN and commercial part number lookups. 7 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled. Unit of issue: EA.

Technical Specifications
ParameterValue
NSN5999-01-033-5474
Primary Part NumberC42121Z21C4
Item NameHeat Sink,electrical-Electronic
FSC / FSG5999 / 59 — No Item Name Available
ManufacturerHensoldt Sensors Gmbh
StatusCANCELLED
MaterialCOPPER ALLOY
Surface Treatment Document and ClassificationMIL-F-495 MIL SPEC SINGLE TREATMENT RESPONSE
Mounting Facility Type and Quantity1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Unthreaded Mounting Hole Diameter0.240 INCHES MINIMUM AND 0.265 INCHES MAXIMUM SINGLE MOUNTING FACILITY IN
Material Document and ClassificationMIL-C-81021 MIL SPEC SINGLE MATERIAL RESPONSE
Surface TreatmentOXIDE
Overall Diameter0.275 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN
MaterialCOPPER ALLOY
Surface Treatment Document and ClassificationMIL-F-495 MIL SPEC SINGLE TREATMENT RESPONSE
Mounting Facility Type and Quantity1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Unthreaded Mounting Hole Diameter0.240 INCHES MINIMUM AND 0.265 INCHES MAXIMUM SINGLE MOUNTING FACILITY IN
Material Document and ClassificationMIL-C-81021 MIL SPEC SINGLE MATERIAL RESPONSE
Surface TreatmentOXIDE
Overall Diameter0.275 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN
Lifecycle & Compliance
Acquisition StatusCANCELLED
Successor5999-01-109-4987 (259869-1)
HAZMATNo
Shelf Life Code0
Criticality CodeN
Unit of IssueEA
SMR CodeYN
Weight0.0100 lbs
Cube0.0010 cu ft
Verified Substitutes 7
5999-01-109-4987259869-1 SUCCESSOR
Heat Sink,electrical-Electronic
Varo Llc
5999-01-326-8159205CB SUCCESSOR
Heat Sink,electrical-Electronic
Goodrich Lighting Systems Inc
1680-00-626-9655371095-1 INTERCHANGEABLE
Track,seat,navigator
Lockheed Martin Corp
5999-01-211-6671NAS4119E04C INTERCHANGEABLE
Heat Sink,electrical-Electronic
National Aerospace Standards Committee Aerospace Industries Association of America Inc Not for Rfq or Solicitation Use
5335-01-435-5067800653 INTERCHANGEABLE
Wire Fabric
Tsi Incorporated
5999-01-475-4019 INTERCHANGEABLE
Heat Sink,electrical-Electronic
5315-01-673-1569800653 INTERCHANGEABLE
Pin,quick Release
Jergens Inc Div Tooling Components Division
Cross-Reference Index
Part NumberManufacturer
C42121Z21C4 Hensoldt Sensors Gmbh (DEU)
800653 Northern Telecom Systems Corp (USA)
205-CB Wakefield Engineering Co (USA)
205-CB Eg and G Wakefield Engineering (USA)
4841-0205-02 Igm Communications Dba Straightline by Igm (USA)
37-1095-1 The Boeing Company Div Legacy Wichita (USA)
580R703H03 Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp (USA)
5800583-097400-022 Hensoldt Sensors Gmbh (DEU)
2889694-2 Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier (USA)
Related Parts
SUCCESSOR 5999-01-109-4987 Heat Sink,electrical-Electronic · 259869-1
5999-01-326-8159SUCCESSOR
HEAT SINK,ELECTRICAL-ELECTRONIC
205CB
1680-00-626-9655INTERCHANGEABLE
TRACK,SEAT,NAVIGATOR
371095-1
5999-01-211-6671INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
NAS4119E04C
5335-01-435-5067INTERCHANGEABLE
WIRE FABRIC
800653
5999-01-475-4019INTERCHANGEABLE
HEAT SINK,ELECTRICAL-ELECTRONIC
5315-01-673-1569INTERCHANGEABLE
PIN,QUICK RELEASE
800653

Frequently Asked Questions

What is NSN 5999-01-033-5474?

NSN 5999-01-033-5474 is a Heat Sink,electrical-Electronic, manufactured by Hensoldt Sensors Gmbh, classified under FSC 5999 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 5999-01-033-5474?

NSN 5999-01-033-5474 has 9 cross-referenced part numbers: C42121Z21C4 (Hensoldt Sensors Gmbh), 800653 (Northern Telecom Systems Corp), 205-CB (Wakefield Engineering Co), 205-CB (Eg and G Wakefield Engineering), 4841-0205-02 (Igm Communications Dba Straightline by Igm) and 4 more.

What NSN replaces 5999-01-033-5474?

There are 7 known substitutes for 5999-01-033-5474: 5999-01-109-4987, 5999-01-326-8159, 1680-00-626-9655 and 4 more. Verify interchangeability with system specifications before substitution.

What are the specifications of C42121Z21C4?

Key specifications for C42121Z21C4: Material: COPPER ALLOY; Surface Treatment Document and Classification: MIL-F-495 MIL SPEC SINGLE TREATMENT RESPONSE; Mounting Facility Type and Quantity: 1 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY; Unthreaded Mounting Hole Diameter: 0.240 INCHES MINIMUM AND 0.265 INCHES MAXIMUM SINGLE MOUNTING FACILITY IN. 16 total characteristics are documented in the Federal Logistics Information System.

Is NSN 5999-01-033-5474 still in active supply?

NSN 5999-01-033-5474 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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