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1000/400/500 Series MIL-C-4109 Industrial Interchange Air Swing Coupling, Female Half With Safety Vent, -04 Coupling, 1/4-18 Female NPT

A 2.54	B 0.79	Coupling Size -04	Brand RTC North America Ltd	Brand RTC North America	Pack Size 1.00	UOM EA	Seal Material Buna-N	Supplier Part Number R20500311	Thread 1 1/4-18	Thread Sealant No	Alternate Part Numbers Alternate Part Number C1ZY90, Alternate Part Number MI-08754629, Alternate Part Number MINO-00691X96666	Product Weight 0.23 lbs

Product Questions & Answers 1

Product Questions & Answers

got a 1/4-18 female NPT air line, is this the right female end for it?

Question by: Randy C on Feb 24, 2026, 8:47 AM

For a 1/4-18 female NPT connection, the thread on this coupling matches that spec. It is the female half and it is a -04 coupling size, with a 360 degree swivel to help keep the hose from kinking once it is hooked up.

Answer by: Customer Support on Feb 26, 2026, 7:47 AM

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Model Number	Coupling Size	Thread 1	Seal Material	A	B
20500026	-06	3/8-18	Buna-N	2.79	0.94
20500110	-08	1/2-14	Buna-N	3.31	1.38
20500311	-04	1/4-18	Buna-N	2.54	0.79