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AR21999 — OSCILLATOR,CRYSTAL CONTROLLED

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

AR21999: OSCILLATOR,CRYSTAL CONTROLLED.

The OSCILLATOR,CRYSTAL CONTROLLED is a the manufacturer industrial component. Key specifications include diameter: 0.219 INCHES NOMINAL ROPE IN, end_type: PLAIN SECOND END, material: ASBESTOS AND CORK OVERALL, base_type: PEDESTAL ON LEGS, back_width: 18.000 INCHES NOMINAL IN, head_style: FLAT COUNTERSUNK. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-277-6199, 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
AR21999
NSN: 4730-00-277-6199
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: Z0944 — HITACHI CONSTRUCTION MACHINERY AUST AUSTRALIA PTY LTD HITACHI CONSTRUCTION MACHINERY (AUS)
SPECIFICATIONS
diameter0.219 INCHES NOMINAL ROPE IN
end_typePLAIN SECOND END
materialASBESTOS AND CORK OVERALL
base_typePEDESTAL ON LEGS
back_width18.000 INCHES NOMINAL IN
head_styleFLAT COUNTERSUNK
lay_methodRIGHT REGULAR ALL LAYERS
seat_depth18.000 INCHES NOMINAL IN
seat_width19.000 INCHES NOMINAL IN
back_height18.000 INCHES NOMINAL IN
leg_quantity5
head_diameter0.308 INCHES MINIMUM AND 0.332 INCHES MAXIMUM IN
NSN4730-00-277-6199
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: AR21999 · 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
SUBSTITUTES & CROSS-REFERENCES 7
QS600M44SReference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
252052Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
44HSReference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
4730001384006Reference document
Same NSN cross-reference
Reference document — Secondary reference
11608950-12Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
1222610-3Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is AR21999?
AR21999 is a OSCILLATOR,CRYSTAL CONTROLLED.
What parts can replace AR21999?
There are 7 known substitutes for AR21999: QS600M44S, 252052, 44HS and 4 more. Substitute compatibility should be verified for your specific system.
What is the NSN for AR21999?
AR21999 is cataloged in the U.S. Government catalog under NSN 4730-00-277-6199. 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.