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HK Series Industrial Interchange Series B Steel Hydraulic Quick Disconnect, Male Half, -06 Coupling, 3/8-18 Female NPT

Description & Features

Designed for a wide range of industrial applications, this hydraulic quick disconnect coupling ensures reliable performance under varying pressure conditions. Its self-sealing poppet valve design guarantees excellent sealing at both high and low pressures. Featuring Buna-N as the standard seal material, it supports a diverse temperature range from -40deg;F to +250deg;F. Seal options include PTFE, Neoprene, FKM, EPDM, and Kalrezreg; for enhanced compatibility.

This coupling meets ISO standard 7241-1 Series B dimensional requirements, facilitating easy and efficient fluid transfer across multiple industrial sectors including agriculture, construction, and chemical industries. The 3/8-18 NPT female thread allows for secure connections, while the push-to-connect male half simplifies installation.

Air inclusion is minimal at 2.90 cubic centimeters, and fluid loss is restricted to 2.10 cubic centimeters, ensuring optimal system efficiency. With a coupling size of -06, it is well-suited for heavy-duty tasks in transportation, military, and aerospace sectors.

ECCN: EAR99

Supplier Part Number: 3K21

Specifications

Brand Danfoss	Connection Size 1 3/8 in	Connection Size 2 3/8 in	Connection Style Manual	Connection Type FNPT	Connection Type 1 Female NPTF	Connection Type 2 Female NPTF	Dimensions 1.01 in Dia x 1.76 in L	Finish Zinc Trivalent	Fitting Type Coupling	Fluid Compatibility Hydraulic Fluids	Hex Size 7/8 in	Latch Type Push/Pull	Material Steel	Material Construction Carbon Steel	Maximum Operating Pressure 4000 psi	Operating Temperature -40 to 250 deg F	Seal Material NBR	Series HK1-8 Series	Thread Size 3/8-18	Valve Type 2-Way

Similar Products

Model Number	Coupling Size	Thread Size	Seal Material	A
2K16 HK Series Quick Disconnect	-04	1/4-18	Buna-N	1.52
1K11 HK Series Quick Disconnect	-02	1/8-27	Buna-N	1.26
4KP26 HK Series Quick Disconnect	-10	1/2-14	Buna-N	2.03
6KP31 HK Series Quick Disconnect	-12	3/4-14	Buna-N	2.36
8KP36 HK Series Quick Disconnect	-16	1-11-1/2	Buna-N	2.85

Product Questions & Answers (2)

Question by: Vince M on Aug 25, 2025, 8:57 PM

i’ve got hoses with 3/8-18 female npt threads, is this the right male quick connect half to screw in?

Answer by: Customer Support on Aug 27, 2025, 6:56 AM

The threaded end on this plug is 3/8-18 NPTF female. The coupling size is -06 and the connection style on the mating side is push to connect, so it is meant to act as the male half in an ISO 7241-1 Series B interchange setup.

Question by: Ralph B on Jul 21, 2025, 9:32 AM

seal material on this thing, is buna-n gonna hold up running hydraulic oil in a shop environment day in and day out?

Answer by: Customer Support on Jul 23, 2025, 6:55 AM

Buna-N holds up well with standard petroleum-based hydraulic fluids, which makes it a solid fit for everyday shop use. The rated temperature range runs from -40°F up to 250°F, so normal operating temps in an industrial or shop setting won't be a problem. If you're running something other than conventional hydraulic oil, like certain synthetics or chemical fluids, there are alternative seal options available including FKM, EPDM, Neoprene, PTFE, and Kalrez, each with their own temperature ceilings. FKM for instance goes up to 400°F, and EPDM tops out at 300°F. For straight hydraulic oil in a general shop environment, the standard Buna-N seal is going to do the job without issue.

HK Series Industrial Interchange Series B Steel Hydraulic Quick Disconnect, Male Half, -06 Coupling, 3/8-18 Female NPT

Description & Features

Specifications

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Product Questions & Answers (2)