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AS21904J4 — INJECTOR ASSEMBLY,FUEL

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

AS21904J4: INJECTOR ASSEMBLY,FUEL.

The INJECTOR ASSEMBLY,FUEL is a the manufacturer industrial component. Key specifications include material: STEEL COMP 304 OVERALL, flow_angle: 90.0 DEGREES, leg_length: 0.875 INCHES NOMINAL FIRST END IN, seat_angle: 12.0 DEGREES ALL ENDS, thread_class: 3A ALL ENDS A, connection_type: THREADED EXTERNAL TUBE ALL ENDS. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-988-4121, 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
AS21904J4
NSN: 4730-00-988-4121
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 81343 — SOCIETY OF AUTOMOTIVE ENGINEERS INC (USA)
SPECIFICATIONS
materialSTEEL COMP 304 OVERALL
flow_angle90.0 DEGREES
leg_length0.875 INCHES NOMINAL FIRST END IN
seat_angle12.0 DEGREES ALL ENDS
thread_class3A ALL ENDS A
connection_typeTHREADED EXTERNAL TUBE ALL ENDS
connection_styleFLARELESS (TUBE) ALL ENDS
surface_treatmentPASSIVATE OVERALL
nominal_thread_size0.438 INCHES ALL ENDS IN
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
specification/standard_data96906-MS21904 GOVERNMENT STANDARD
material_document_and_classification66 FED STD SINGLE MATERIAL RESPONSE OVERALL
NSN4730-00-988-4121
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: AS21904J4 · OEM ⚠ VERIFY BEFORE ORDERING NPT ≠ BSPT — tapered threads look identical but are NOT interchangeable. Wrong thread = leak. JIC (37°) ≠ AN (37°) ≠ SAE 45° — flare angles must match exactly. Measure thread pitch with gauge — visual identification is unreliable ✓ BROKER TIP Always use thread sealant (PTFE tape or pipe compound) on tapered threads (NPT/BSPT). JIC/AN flare fittings seal metal-to-metal — never use tape on flare connections PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
FLOW ANGLE: 90.0 DEGREES
•
CONNECTION STYLE: FLARELESS (TUBE) ALL ENDS
•
CONNECTION TYPE: THREADED EXTERNAL TUBE ALL ENDS
•
MATERIAL DOCUMENT AND CLASSIFICATION: 66 FED STD SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED: 0.250 INCHES ALL ENDS IN
•
LEG LENGTH: 0.875 INCHES NOMINAL FIRST END IN
•
NOMINAL THREAD SIZE: 0.438 INCHES ALL ENDS IN
•
SEAT ANGLE: 12.0 DEGREES ALL ENDS
TECHNICAL CHARACTERISTICS
FLOW ANGLE90.0 DEGREES
CONNECTION STYLEFLARELESS (TUBE) ALL ENDS
CONNECTION TYPETHREADED EXTERNAL TUBE ALL ENDS
MATERIAL DOCUMENT AND CLASSIFICATION66 FED STD SINGLE MATERIAL RESPONSE OVERALL
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED0.250 INCHES ALL ENDS IN
LEG LENGTH0.875 INCHES NOMINAL FIRST END IN
NOMINAL THREAD SIZE0.438 INCHES ALL ENDS IN
SEAT ANGLE12.0 DEGREES ALL ENDS
SPECIFICATION/STANDARD DATA96906-MS21904 GOVERNMENT STANDARD
SURFACE TREATMENTPASSIVATE OVERALL
SUBSTITUTES & CROSS-REFERENCES 7
AS21904Reference document
Same NSN cross-reference
Reference document — Secondary reference
AP2851J04Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
MS21904J4Reference document
Same NSN cross-reference
Reference document — Secondary reference
AS18280Reference document
Same NSN cross-reference
Reference document — Secondary reference
SAE-AS18280Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
MS21904-4JReference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is AS21904J4?
AS21904J4 is a INJECTOR ASSEMBLY,FUEL.
What parts can replace AS21904J4?
There are 7 known substitutes for AS21904J4: AS21904, AP2851J04, MS21904J4 and 4 more. Substitute compatibility should be verified for your specific system.
What is the NSN for AS21904J4?
AS21904J4 is cataloged in the U.S. Government catalog under NSN 4730-00-988-4121. 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.