A Comprehensive Guide to All Connection Types

In this blog post, you’ll read:Understanding the myriad of plumbing connection types is crucial for effective plumbing work. From the versatile threaded connections with male and female threads to the secure fit of barbed inserts and the simplicity of push-fit connectors, each type serves a unique purpose. Specialty connections like twist and lock, flare, and compression offer solutions for specific tubing materials and applications, while crimp and cold expansion are ideal for PEX tubing.
Table of Contents

Learning about connection types can be a daunting task. Numerous kinds of connections exist, some of which are nearly identical to one another. We’ll discuss a variety of connections here, along with how they differ to help you recognize them.
It may not be easy to distinguish certain connection types because they even have mixtures of other connections. We’ve included graphic demonstrations for each link to make things easier for you.

Here’s a list of connections that we’ll be covering in this article:

  1. Threaded
  2. Barbed / Insert
  3. Mini Barb / Poly Barb
  4. Combination Nipples / Hose Menders
  5. Slip / Socket / Spigot
  6. Push-Fit
  7. Twist and Lock
  8. Plastic Quick Connect
  9. Flare
  10. Compression
  11. Garden Hose
  12. Solder / Copper
  13. Crimp / Cold Expansion


During your plumbing career, threaded connectors must have come across for you. They are the main element in the majority of fittings.

Male pipe thread (MPT) and female pipe thread (FPT) are the two different types of threads. The male and female threads are positioned inside and outside the connector, respectively, which is the sole distinction.

fip mpt brass reducing coupling fitting
fip mpt brass reducing coupling fitting


Other terminology that you may have encountered is Iron Pipe Size (IPS), sometimes known as Male Iron Pipe (MIP) or Female Iron Pipe (FIP). The fact that these are different designations for MPT and FPT may surprise you.

FPT pipe fitting ss316
FPT pipe fitting ss316



FPT Barbed / Insert

Barbed connections are also relatively frequent, much like threaded connections. Because of the way they are made, they fit into the tube and stay there considerably more securely. It’s not too difficult to distinguish between threaded and barbed connections based on the images.
Have you never heard of barbed? This name may know it: Put in place, they are both the same! There are variations among all the barbed connectors. The barbs could be big, tiny, or more widely spaced. Everything relies on the kind of connection they are utilized for.

Mini Barb / Poly Barb

Mini barbs, sometimes poly barbs, are smaller than standard barbed fittings. They are extremely vibration-resistant and are utilized for polyethylene tubing.

Mini barb poly barb
Mini barb poly barb

Combination Nipples / Hose Menders

Hoses are connected to pipelines or valves using combination nipples. Hose menders are utilized to join disconnected hose sections or fix broken ones.
Straight-end natural rubber and thermoplastic hoses are the most common uses for combination nipples or hose menders since these fittings’ barbs are made especially for connections of this kind.

Slip / Socket & Spigot

PVS fittings that are Sch 40 and Sch 80 typically employ these connectors. The slip/socket is sometimes referred to as the hub or the “Female” connection of PVC fittings.

The connection’s spigot end is placed into the Slip/Socket. It is referred to as the PVC fittings’ “Male” connection. Its exterior diameter is the same as that of the pipe.

Slip socket and spigot
Slip socket and spigot.


These connections must be familiar to you from several fittings and ball valves. Push-fit connections are typically utilized when connecting copper tube size (CTS) CPVC or PEX. Since these are considerably smaller than NPT, push-fit connections can be installed in NPT pipes.

CTS tubing fits over the tube support tightly and requires only a push, unlike large NPT pipes. Many pipe fitting manufacturers have a specialized disconnect tool, so you can disconnect and reuse the tubing when modifications are needed.

Push fit

Twist and Lock

A combination of compression and push-fit technologies is used in these connections. Please put them in the tube by locking the nut clockwise to secure them. Twist and lock connections get their name for just this reason.


Twist and lock
Twist and lock

Plastic Quick Connect

Although push-fits and plastic quick-connect connections may be confusing, they are different. To create a secure connection with a plastic quick connect, the tube is pushed into the fittings socket until it meets the tube stop.

Plastic quick connect
Plastic quick connect


Only flare fittings should be used with flare connectors. As you can see in the picture, the threads on these fittings stop short of the end. Flare fittings are standard with metal tubing and function somewhat like compression fittings. There are two primary types of connectors: male flare and female flare.



Compression fittings are the main use for compression connections. As you can see in the picture, they are composed of three parts. Compression fittings operate similarly to how a nut is tightened on a sleeve. They are frequently used to connect polyethylene or copper tubing. Sometimes, compression fittings are referred to as CPs.


Garden Hose

There are two varieties of garden hose thread (GHT): male (MGHT) and female (FGHT). Even though GHTs have threads, they are incompatible with NPT. Water hose fittings have these connectors. MPT is visible in the top portion of the image, whereas MGHT is in the bottom portion.

Solder / Copper

In the past, this connection was made more frequently. But soldering isn’t as common these days due to the dangers involved. Solder is used to fill the spaces created by inserting the copper pipe into the fitting in this connection.

Solder copper fitting
Solder copper fitting

Crimp / Cold Expansion

When using pex tubing, these connectors work best. The fitting is fitted with the pipe using a crimp tool. The tube is fitted with a crimp ring to secure the connection. Next, the ring is placed on one of the fitting’s ribs. An old expansion has a twist, much like a crimp connector. We utilize a sleeve instead of a ring. The procedure follows: we place the sleeve over the PEX tubing, stretch it out, insert the fitting, and allow it to contract again. The connection is safeguarded in this way.

Parting Words

There you have it, then! This was an exhaustive list of all the connection types you might come across in the plumbing industry if you have any more questions or concerns. We’ll respond to any comments you leave below.


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