PEX Fittings

PEX Fittings are used to make PEX to PEX Connections, to connect PEX to a manifold, & to connect PEX to another material. Several varieties of Radiant Heat Fittings are available.

Tools to Help You Choose



PEX fittings are used to connect PEX Tubing to manifolds, copper, PEX, faucets, fixtures, and many other products. There are several different styles of PEX Fittings and all of them have different requirements for tubing, tools, and rings. To make it easy, it is best to choose one system for all connections and use that system for fittings, tool, and rings throughout your entire home. To decide which system is best for you, you can watch our video describing each system, read our FAQs and look through the various charts in this section.

Need more help finding what you need?

1-888-757-4774 Monday - Thursday:
8am to 5:45pm
9am to 4:45pm


  • With so many PEX fitting systems available, how do I know which one is right for me?

    There are many different PEX fitting systems available today. To figure out which fitting system is best for you, you can think about the following questions:

    Are you working on a small, one time job, or are you working on a large job or are you likely to work with PEX again?

    If you are working on a small, one time job the best fittings for you are either the SharkBite fittings, or the clamp tool with crimp fittings. These are the only connection systems that don't require the purchase of an expensive tool. If you are going to be working with PEX on a regular basis, or if you have a large job, you can use either the Expansion system, press system, or the crimp/clamp system.

    Are you an experienced DIY, or are you a beginner?

    The easiest fitting system to work with is SharkBite, followed by the clamp fitting system. The expander, crimp, and press methods are better suited for experienced DIY's or professionals.

    Do you want the biggest and best brand name, or is brand not an issue?

    The Uponor Wirsbo Expansion system is the most recognized connection system amongst professionals. Uponor is the world leader in the production of PEX and its fitting system has been used for over 30 years. The Viega Press system is also gaining popularity among trade professionals and DIY's. There are crimp and clamp systems made by many different manufacturers and most of the products are comparable to each other.

    How important is price to you?

    Prices of PEX tools and fittings vary substantially. The Wirsbo expander and Viega press tools are more expensive, while the crimp and clamp tools are much less expensive. If you are price conscious, the crimp or clamp system will be the most inexpensive, and still provide a quality PEX connection. If quality is your main concern, the Wirsbo or Viega systems are preferable.

  • Which fitting systems can be used with which tubing?

    There is a chart in this help section that shows which tubing can be used with which fittings. In general, all crimp and clamp style connection systems can be used with all standard PEX tubing (not including PEX-AL-PEX Tubing). However, the Wirsbo Expansion system can only be used with PEX-a tubing such as AquaPEX, hePEX, or MrPEX.

  • Do any of the fittings work without a tool?

    Yes. The SharkBite fittings are push-fit and don't require a PEX tool. These fittings are great for small jobs, or jobs that need to be done very quickly, such as stopping a leak. There are also compression style PEX fittings that may be used with PEX Tubing. These fittings allow you to connect from PEX to PEX, copper, or threaded pipe without a tool.

  • Which rings or clamps go with which fittings?

    The ProPEX plastic rings go with ProPEX Fittings. Stainless steel clamps go with HydroPEX fittings if you are using a clamping tool. Copper crimp rings go with HydroPEX Fittings if you are using a crimping tool. PEX Press Sleeves go with Viega PEX Press Fittings. SharkBite Fittings and compression fittings require no additional parts.

  • Do customers ever mix up their orders with different fittings?

    Yes they do, here is an article from our blog about this exact issue:
    While sorting through the orders yesterday to get them ready to ship, we came across one with a mixture of ProPEX fittings, a HydroPEX Clamp Tool, HydroPEX rings, and HydroPEX tubing. This raises a red flag for us because these parts are not all compatible. All of the HydroPEX items work great together, but those ProPEX Fittings will not work with the tool, tubing or the rings on this order. And, if the customer wanted to make connections, he would need some HydroPEX Fittings to do so. Now sometimes, customers are purchasing for multiple jobs, have a few different tools that they use, or are picking up a few items for someone else where they actually do want several connection systems that are not compatible with each other. But just to be sure, we pick up the phone.

Need more help finding what you need?

1-888-757-4774 Monday - Thursday:
8am to 5:45pm
9am to 4:45pm

Comparison Guide


PEX Fittings Compatability Chart

  Uponor Expander Fittings Viega Press Fittings Crimp Fittings Sharkbite Fittings Compression Fittings
Compatible Tubing AquaPEX ViegaPEX AquaPEX AquaPEX AquaPEX
  hePEX FostaPEX hePEX hePEX hePEX
  MrPEX AquaPEX HydroPEX HydroPEX HydroPEX
HydroPEX ViegaPEX ViegaPEX Multicor1
ThermaPEX WattsPEX WattsPEX ThermaPEX
WattsPEX ThermaPEX
Tool Options Manual Expander Tool Manual Press Tool Clamp Tool None Required None Required
Air Expander Tool Battery Press Tool Crimp Tool
Battery Expander Tool
Required Rings Uponor Expander Rings Press Sleeves Clamps or Crimps Rings None None

1. These fittings are for use with aluminum PEX

Manuals -

PEX Radiant Compression Fittings

Wirsbo QS-Style PEX Fittings are compression PEX fittings. These fittings don't requ

PEX Crimp Fittings

These PEX fittings may be used with the stainless steel clamping system or the copper

ProPEX Expander Fittings

ProPEX Fittings are expansion style fittings. These PEX Fittings are manufactured by

SharkBite Push-Fit Fittings

SharkBite Push-Fit Fittings are designed to simplify pipe installation. The fittings

Multipress (MLC) PEX-AL-PEX Fittings

Wirsbo Multipress Fittings make connections for PEX-Aluminum-PEX Tubing. A manual or

PEX Press Fittings

The Viega PEX Press fitting system meets strict ASTM standards in addition to UPC and

Onix Fittings

This category contains Onix fittings manufactured by Watts.

PEX Press Polymer Fittings

This category contains Pex Press Polymer Fittings manufactered by Viega. The new Vie

More About PEX Fittings

PEX fittings are used to make connections from PEX tubing to PEX tubing, PEX tubing to manifolds, PEX tubing to copper, and PEX tubing to faucets & fixtures, among other applications. Fittings are commonly made of brass, but are also available in plastic, bronze, and stainless steel.

Advantages of PEX fittings include cost effectiveness, flexibility, and durability when compared to traditional copper fitting alternatives. Due to the flexibility of PEX, a standard installation will require less connections than if the same installation was performed using traditional copper pipe and fittings. Consequently, having fewer connection requirements means less fittings and lower labor costs. Also, fewer fittings in the system means less leak potential.

Connection Methods
PEX fittings are available in many different connection methods which vary from manufacturer to manufacturer. Each connection method may require a specific tool dedicated to completing a successful connection. Common connection methods include: Uponor (Wirsbo) ProPEX, Crimp, Clamp, Compression, and Push-Fit connections.

ProPEX Expander Fittings
ProPEX expander fittings are manufactured by Uponor (Wirsbo). ProPEX expander fittings require the Milwaukee ProPEX expander tool and a ProPEX ring to secure a successful connection. These fittings can only make connections in PEX-a tubing (Engel method) applications. ProPEX expander fittings are available in brass or an engineered plastic version, which is more cost effective but just as reliable.

Rifeng Crimp Fittings
Crimp/clamp fittings are the most simple and most often used by DIYs; however they are also popular with professionals in certain areas of the United States. Crimp/clamp fittings require a crimp tool which uses copper crimp rings or a clamp tool which uses a stainless steel clamp ring to secure a successful connection. Many DIYs prefer the clamp tool because it is slightly easier to use and cheaper than the crimp tool. These PEX fittings may be used for PEX plumbing applications. They allow connections while using PEX tubing. These fittings meet the ASTM F1087 standard. Rifeng fittings may be used with AquaPEX, HePEX, ThermaPEX, Zurn PEX, Watts PEX, Vanguard PEX, and Viega PEX Tubing.

Compression Fittings
A compression fitting consists of three parts: a compression nut, a compression ring, and a compression insert. Compression fittings do not require a special tool, making it simple for DIYs to install. One major advantage of compression fittings is their simplicity of assembly and disassembly when a repair is needed. Compression fittings are a great choice when a repair or small number of connections is required and purchasing an expensive tool is unwarranted. Wirsbo QS-Style PEX fittings are compression PEX fittings which don't require a special tool. When using PEX-al-PEX tubing, you will need to use a combination of the Multicor fitting assemblies and the QS-style adapters. When using other types of PEX Tubing (ie ThermaPEX or hePEX) you will need to use a combination of the QS-style fitting assemblies and the QS-style adapters. One of each is required per connection.

Push-Fit Fittings
Push-Fit fittings are similar to compression fittings in that they are designed to connect to PEX in a matter of seconds. SharkBite Push-Fit fittings, the most popular push-fit fittings, are designed to simplify pipe installation. Push-Fit fittings can be disconnected and they remove the risk of any scale build up. Because of their flexibility, Push-Fit fittings reduce installation time without the need for special tools. John Guest also manufactures reliable Push-Fit fittings and is best known for their Speedfit Series. Push-Fit fittings have a body composed of solid DZR brass and are compatible with any standard ASTM size PEX, copper tubing, and CPVC. However, Push-Fit fittings are not compatible with PEX-AL-PEX Tubing.

Multipress PEX-AL-PEX Fittings
Wirsbo Multipress fittings make connections to PEX-AL-PEX tubing. An MLC press tool is required to make successful connections from an MLC fitting to PEX-AL-PEX tubing. The MLC press manual tool kit is compatible with 1/2" & 5/8" MLC press fittings. The mini-press battery tool is an electro-hydraulic model that makes fast, easy connections to PEX-AL-PEX Tubing and is compatible with 1/2" to 1" PEX-AL-PEX.

Onix Fittings
Watts Onix fittings are specifically designed for Onix tubing. Onix tubing is an EPDM-based, aramid fiber reinforced tube with an aluminum oxygen barrier. Onix tubing is used in radiant heat and snow melt applications. Onix fittings require SqueezeTite Pliers and SelfTite clamps to make successful connections.