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Hexagonal malleable iron coupling with female threaded ends

Value Brand

Value Brand 5P551 Coupling 3/8" FNPT Malleable Iron Class 150

SKU CH-2DKB-K8X4X

A 3/8 inch FNPT malleable iron Class 150 coupling for connecting threaded pipes

  • Malleable iron construction withstands Class 150 pressure ratings
  • Female NPT threads accept 3/8" pipe connections directly
  • Straight coupling design joins two pipe sections inline
  • ZORO SELECT brand ensures consistent manufacturing quality
  • New condition guarantees full material integrity and performance

3/8" Malleable Iron Coupling

The Value Brand 5P551 coupling joins two 3/8" FNPT threaded pipes in a straight line. Made from malleable iron rated to Class 150, it suits water, air or oil lines in residential and light-commercial plumbing. The female threads on both ends accept standard NPT pipe nipples or fittings. New condition ensures clean threads and no prior stress.

Installers needing a 3/8" straight connector

This coupling fits only 3/8" FNPT threads; it will not join larger or smaller pipe sizes, nor will it adapt to compression, flare or push-fit connections. Builders who need a reducing coupling, a union for frequent disassembly, or a different material such as brass or stainless steel should select another fitting.

Thread sealant and a wrench are all that is required

Apply PTFE tape or pipe dope to the male threads before tightening to prevent leaks. Over-tightening can crack the malleable iron body, especially on smaller 3/8" sizes. Ensure the pipe ends are clean and cut square so the threads engage fully without cross-threading.

Highlights

  • Malleable iron construction withstands Class 150 pressure ratings
  • Female NPT threads accept 3/8" pipe connections directly
  • Straight coupling design joins two pipe sections inline
  • ZORO SELECT brand ensures consistent manufacturing quality
  • New condition guarantees full material integrity and performance

Specifications

BrandZORO SELECT

Questions about this item

What pipe size and thread type does this 3/8 inch FNPT malleable iron coupling need to connect to?

It connects to 3/8 inch male NPT threaded pipe or fittings on both ends.

Can this Class 150 coupling be used with older galvanised steel pipe that has the same 3/8 inch thread?

Yes, the FNPT threads are compatible with standard 3/8 inch male NPT threads on galvanised steel pipe.

How can I confirm the coupling is rated for the correct pressure class after installation?

The body is marked Class 150 and the ZORO SELECT brand identifies the manufacturer.

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