PartsTable
Technical Data Sheet
PartsTable / COMPONENT / 123721-1
123721-1 ✓ Verified by PartsTable
— · HOSE FITTING
WHAT YOU NEED TO KNOW
PTFE tape on tapered threads (NPT/BSPT) JIC/AN flare connections seal metal-to-metal — no tape
NPT != BSPT — look identical, NOT interchangeable
PRODUCT OVERVIEW

The COUPLING,BOSS is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, thread_class: 3B ALL ENDS, connection_type: THREADED INTERNAL BOSS FIRST END, connection_style: GASKET SEAL (BOSS) ALL ENDS, style_designator: PLAIN, surface_treatment: PASSIVATE INSIDE. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 4730-00-803-5912, 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
123721-1
NSN: 4730-00-803-5912
FSC: 4730
CAGE: 24390 — NATIONAL SERVICE INDUSTRIES INC DBA ZEP MFG CO (USA)
SPECIFICATIONS
materialSTEEL OVERALL
thread_class3B ALL ENDS
connection_typeTHREADED INTERNAL BOSS FIRST END
connection_styleGASKET SEAL (BOSS) ALL ENDS
special_features2.312 IN.DIA BY 0.188 IN.THD FLANGE W/FOUR 0.220 IN.MIN/0.226 IN.MAX DIA HOLES EQUALLY SPACED ON 1.875 IN.DIA BOLT CIRCLE,LOCATED 0.312 IN.FROM END IN
style_designatorPLAIN
surface_treatmentPASSIVATE INSIDE
nominal_thread_size0.750 INCHES FIRST END IN
nominal_overall_length2.688 INCHES IN
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
material_document_and_classification66,AISI 302/SAE 30302 FED STD SINGLE MATERIAL RESPONSE OR 66,AISI 304/SAE 30304 FED STD SINGLE MATERIAL RESPONSE OVERALL
NSN4730-00-803-5912
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: 123721-1 · 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
•
THREAD SERIES DESIGNATOR: UNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
•
CONNECTION STYLE: GASKET SEAL (BOSS) ALL ENDS
•
CONNECTION TYPE: THREADED INTERNAL BOSS FIRST END
•
SURFACE TREATMENT: PASSIVATE INSIDE
•
NOMINAL OVERALL LENGTH: 2.688 INCHES IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: 66,AISI 302/SAE 30302 FED STD SINGLE MATERIAL RESPONSE OR 66,AISI 304/SAE 30304 FED STD SINGLE MATERIAL RESPONSE OVERALL
•
MATERIAL: STEEL OVERALL
•
NOMINAL THREAD SIZE: 0.750 INCHES FIRST END IN
TECHNICAL CHARACTERISTICS (FLIS)
THREAD SERIES DESIGNATORUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
CONNECTION STYLEGASKET SEAL (BOSS) ALL ENDS
CONNECTION TYPETHREADED INTERNAL BOSS FIRST END
SURFACE TREATMENTPASSIVATE INSIDE
NOMINAL OVERALL LENGTH2.688 INCHES IN
MATERIAL DOCUMENT AND CLASSIFICATION66,AISI 302/SAE 30302 FED STD SINGLE MATERIAL RESPONSE OR 66,AISI 304/SAE 30304 FED STD SINGLE MATERIAL RESPONSE OVERALL
MATERIALSTEEL OVERALL
NOMINAL THREAD SIZE0.750 INCHES FIRST END IN
STYLE DESIGNATORPLAIN
THREAD CLASS3B ALL ENDS
VERIFIED SUBSTITUTES & CROSS-REFERENCES 4
12372-1Interchangeable
interchangeable cross-reference
interchangeable
MS3Interchangeable
interchangeable cross-reference
interchangeable
S-048-4Interchangeable
interchangeable cross-reference
interchangeable
GGG-K-275 TY2CL1Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is 123721-1?
123721-1 is a COUPLING,BOSS.
What parts can replace 123721-1?
There are 4 known substitutes for 123721-1: 12372-1, MS3, S-048-4 and 1 more. Substitute compatibility should be verified for your specific system.
What is the NSN for 123721-1?
123721-1 is cataloged in the Federal Logistics Information System (FLIS) under NSN 4730-00-803-5912. 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