Sioux Chief PEX x PB Crimp Bar...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$2.51
Sioux Chief PEX x PB Crimp Barb Adapter, Polybutylene Transition Fitting

Sioux Chief PEX x PB Crimp Barb Adapter, Polybutylene Transition Fitting

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Model: 645X2G

In Stock (leaves warehouse same day if ordered before 3pm ET)

$2.51
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Sioux Chief PEX x PB Crimp Barb Adapter, Polybutylene Transition Fitting

The Sioux Chief PEX x PB barb adapter is a rough-in fitting built for plumbers transitioning an existing polybutylene (PB) line to new PEX SDR9 tubing. This family of dual-barb adapters is available in sizes from 1/2" through 3/4", covering both the 645X2G and 645X3G models, so installers can match the adapter to the existing PB run size on the job. Each adapter ships bagged with one natural copper PB crimp ring and one black copper PEX crimp ring, giving the installer both crimp rings needed to make a complete, mechanically sound transition on a single fitting without sourcing additional hardware. This is a behind-the-wall rough-in part intended for use with PEX SDR9 tube only — not a decorative or exposed fixture.

Key Features

  • Trade Size Range: available from 1/2" PEX x 1/2" PB up to 3/4" PEX x 3/4" PB, sized for standard tube transitions.
  • Dual-Barb Adapter: one end barbed for PEX SDR9 tube, the other barbed for PB tube, allowing a direct splice between the two pipe systems.
  • Included Crimp Rings: bagged with one natural copper PB crimp ring and one black copper PEX crimp ring so both ends of the joint can be completed from the same package.
  • PB-to-PEX Retrofit: purpose-built for adapting older polybutylene supply lines to new PEX lines during repairs or remodels.
  • PEX SDR9 Compatibility: intended for use with PEX SDR9 tube only — confirm tube type before installation.
  • Crimp Connection: barb-and-crimp-ring joint method on both the PEX and PB ends for a mechanically secured connection.

Technical Specifications

  • Country of Origin: United States
  • Packaging: 50 EA per case
  • Models: 645X2G (1/2" PEX x 1/2" PB), 645X3G (3/4" PEX x 3/4" PB)

Typical Applications

  • Repair and Replacement of Polybutylene (PB) Supply Lines
  • PB-to-PEX Retrofit and Remodel Work
  • Residential Rough-In Plumbing Behind Walls and Floors
  • Service Repairs on Mixed PB/PEX Plumbing Systems

Why Sioux Chief?

Sioux Chief supplies this PEX x PB barb adapter family complete with both the PB and PEX crimp rings needed to finish the joint, cutting down on separate hardware sourcing for plumbers handling PB-to-PEX transitions. Built for use with PEX SDR9 tube and manufactured in the United States, these 645X2G and 645X3G adapters are straightforward, job-ready fittings for rough-in service and remodel work across a range of common tube sizes.

Manufacturer Resources

Spec Sheet

Product Specs

Product Type:
Barb Adapter
Connection Type:
Crimp
Country of Origin:
United States
Department:
Plumbing
Product Group:
Rough-In and Supports
Product Subgroup:
Fittings and Valves
Product Size:
3/4"

Sioux Chief 645X2G – Frequently Asked Questions

1) Can I use a Sioux Chief PEX x PB barb adapter to splice new PEX onto an existing polybutylene line?
That's exactly what the Sioux Chief 645X series barb adapter is for. One end is barbed for PEX SDR9 tube, the other is barbed for PB tube, so you cut back the old polybutylene, slide the adapter in, and crimp both ends. No soldering, no separate coupling. It's a behind-the-wall rough-in fitting, so plan on it being covered, not exposed.
2) Do I need to buy crimp rings separately for a PB to PEX transition fitting?
No. Each adapter is bagged with both rings you need: one natural copper PB crimp ring and one black copper PEX crimp ring. The two rings are not interchangeable, which is why both ship together. You'll still need a crimp tool and jaws sized for the trade size you're working in.
3) What sizes does the Sioux Chief PEX x PB crimp adapter come in?
Two sizes, matched end to end: 1/2 inch PEX x 1/2 inch PB (model 645X2G) and 3/4 inch PEX x 3/4 inch PB (model 645X3G). Size to the existing PB run you're cutting into. There is no reducing version in the family, so a 3/4 inch PB line transitioning to 1/2 inch PEX needs a separate reducer downstream of the adapter.
4) Will this barb adapter work with PEX-B or any PEX tubing I have on the truck?
It's specified for PEX SDR9 tube only. SDR9 is the standard dimension ratio for ASTM PEX tubing used in potable water, so most crimp-style PEX on a plumbing truck qualifies, but confirm the print on the tube before you crimp. The PB end is barbed for polybutylene tube and should not be used on PEX.
5) Should I use a PB transition adapter or just repipe the whole polybutylene run?
The 645X series adapter is the repair-and-remodel answer: it lets you keep a sound section of existing PB and tie new PEX to it at a single joint, which is what you want on a service call or a partial remodel. If the PB itself is failing throughout, a transition fitting only moves the problem downstream, and full replacement is the better call. Many plumbers use these adapters progressively, converting the system section by section.
6) Are Sioux Chief 645X barb adapters sold individually or by the case?
Case packaging is 50 each. Each fitting comes bagged with its two crimp rings, so a case gives you 50 complete transitions.
7) Is this polybutylene transition fitting made in the USA?
Yes, the Sioux Chief 645X2G and 645X3G barb adapters are manufactured in the United States, which matters if you're buying under domestic-preference procurement rules for a government or institutional job.
How fast can I get the Sioux Chief 645X2G delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Sioux Chief 645X2G come with a warranty?
Absolutely. The Sioux Chief 645X2G is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Sioux Chief 645X2G?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Sioux Chief 645X2G from ZenSupply?
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