A Guide to Air Compressor Fittings

Posted on: July 26, 2021

Air compressor fittings are essential to keeping your unit running efficiently and delivering the air power you require for your operations. Knowing the types of air compressor fittings available is essential to choosing the right components for your specific model, so the experts at Quincy Compressor compiled this guide to help you determine the sizes and styles you need.

With Quincy Compressor, you can keep your air compressor running smoothly.

What Are Air Compressor Fittings?

Air compressor fittings are attachments that maintain a consistent flow of air and pressure throughout the compressor. Each fitting has a different role, but they are all crucial to managing your unit’s health and functionality.

When it’s time to replace the fittings on your air compressor, you want to start by checking the size you need. Most air compressor fitting sizes follow the National Pipe Tapered (NPT) standard, which denotes the thread size. Using an NPT chart, you should measure and determine the size of your pipes for a fitting. With that information, you can source the various air compressor fittings you may need.


Couplers facilitate the connection of an air tank or air compressor to the air lines. When the air hose is disconnected, the coupler closes to prevent air from escaping. Couplers come in a range of styles, including automotive, industrial, ARO and V-style.

There are two main types of couplers — automatic and manual. Automatic fittings allow you to plug your air lines in directly. They also quickly seal the air opening when the hose or male part is removed, allowing the O-ring or female connection to close completely. Manual couplers require you to pull on the collar of the coupler to insert and remove the air hose. When you remove the line, hold it tightly — the coupler will abruptly expel the tool as compressed air escapes.


Couplers and plugs go together. Whichever style you choose for your coupler, you need the same style for the plug. The essential piece of information you need to decide on a plug is the flow size, or the volume of air the plug can manage. Most standard air compressors require a plug with a 1/2-inch or 1/4-inch flow size, with the latter being more common.

Just like couplers, plugs come in automotive, industrial, ARO and V-style designs. The style of fitting you choose comes down to personal preference, although automotive and industrial variants are more common and easier to find at chain hardware stores. Quality and fit are the most important factors when buying an air compressor plug, so opt for a brand with known quality to prevent compressed air leaks.


Because there are so many different compressed air fitting types, manufacturers have come to recognize how difficult it can be to find the one you need. That’s why companies have begun to color-coordinate their couplers and plugs. For example, you may find a company that matches colors with the following classes:

  • Red for Automotive
  • Green for Industrial
  • Blue for ARO
  • Yellow for V-style

Contact Quincy Compressor With Questions

Choosing the right fittings can be just as important as selecting an air compressor. This quick guide to air compressor fittings should get you started, but if you need further assistance, the team at Quincy Compressor is here to help. Our air experts can answer your questions and help you find the equipment you need to keep your air compressor at its best.

Browse our products today and contact us with any questions!