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Technical Data Sheet
PartsTable / COMPONENT / 21B
21B ✓ Verified by PartsTable
HP · COMPONENT
WHAT YOU NEED TO KNOW
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Confirm exact part number — similar PNs may be different parts
PRODUCT OVERVIEW

The RETAINER,ELECTRON TUBE is a HP industrial component. Key specifications include phase: SINGLE, end_type: EXTERNAL THREAD FIRST END, material: STEEL CORROSION RESISTING, design_type: DOUBLE END, intake_hole: NOT INCLUDED, swage_depth: 0.093 INCHES IN. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 4310-00-035-7510, 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
21B
NSN: 4310-00-035-7510
FSC: 4310
CAGE: 93236 — DRESSER-RAND CO WORTHINGTON COMPRESSOR OPN A JOINT VENTURE (USA)
SPECIFICATIONS
phaseSINGLE
end_typeEXTERNAL THREAD FIRST END
materialSTEEL CORROSION RESISTING
design_typeDOUBLE END
intake_holeNOT INCLUDED
swage_depth0.093 INCHES IN
current_typeAC
storage_typeGENERAL PURPOSE WAREHOUSE
valve_recessNOT INCLUDED
bore_diameter5.000 INCHES NOMINAL IN
luminous_dialNOT INCLUDED
overall_width8.250 INCHES NOMINAL IN
NSN4310-00-035-7510
COMPONENT DIAGRAM
COMPONENT MAIN IC EDGE CONNECTOR MFR: HP RETAINER,ELECTRON TUBE TITLE COMPONENT PN 21B MFR HP RETAINER,ELECTRON TUBE
KEY FEATURES
•
FLANGE OUTSIDE DIAMETER: 5.751 INCHES NOMINAL IN
•
INTAKE HOLE: NOT INCLUDED
•
BOTTOM CHAMFER LENGTH: 0.250 INCHES NOMINAL IN
•
BORE DIAMETER: 5.000 INCHES NOMINAL IN
•
DESIGN TYPE: DRY
•
BODY OUTSIDE DIAMETER: 5.503 INCHES NOMINAL IN
•
STYLE DESIGNATOR: DRY, FLANGED, RELIEVED
TECHNICAL CHARACTERISTICS (FLIS)
FLANGE OUTSIDE DIAMETER5.751 INCHES NOMINAL IN
INTAKE HOLENOT INCLUDED
OVERALL LENGTH13.500 INCHES NOMINAL IN
BOTTOM CHAMFER LENGTH0.250 INCHES NOMINAL IN
BORE DIAMETER5.000 INCHES NOMINAL IN
DESIGN TYPEDRY
BODY OUTSIDE DIAMETER5.503 INCHES NOMINAL IN
STYLE DESIGNATORDRY, FLANGED, RELIEVED
BOTTOM INSIDE CHAMFERINCLUDED
TOP INSIDE CHAMFERNOT INCLUDED
VERIFIED SUBSTITUTES & CROSS-REFERENCES 16
MS17121-6Interchangeable
interchangeable cross-reference
interchangeable
21BInterchangeable
interchangeable cross-reference
interchangeable
306-0251-00Interchangeable
interchangeable cross-reference
interchangeable
1223Interchangeable
interchangeable cross-reference
interchangeable
1161Interchangeable
interchangeable cross-reference
interchangeable
59-205AInterchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is 21B?
21B is a RETAINER,ELECTRON TUBE manufactured by HP.
What parts can replace 21B?
There are 16 known substitutes for 21B: MS17121-6, 21B, 306-0251-00 and 13 more. Substitute compatibility should be verified for your specific system.
What is the NSN for 21B?
21B is cataloged in the Federal Logistics Information System (FLIS) under NSN 4310-00-035-7510. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026