There are literally hundreds of different types of air intake hose fittings or couplings. These fittings are a crucial part for connecting an air hose with pneumatic tools and instruments. Air compressor tools are used in numerous industries from automotive to medical, so it is wise to choose the right type of fitting.

Type of Connections

Chicago style coupling – This is commonly used and recommended for pneumatic rubber hose connections. It is a “sexless coupling” used in air and water services, where a rubber seal in both parts allows a positive leak-proof connection. It is considered to be the most universal as the two-lug head can be used on all sizes without the need of reducing pieces.

Ground joint – Also known as Boss coupling are primarily used for compressed air or steam. This all-purpose connection consists of a stem, wing nut and spud. To achieve both a mechanical and pressure seal this connection uses a wing nut to join the stem and spud together.

Quick release fittings – These fittings are the most reliable and easiest type of coupling an air hose with tools. The two main types of fittings are automotive and industrial where the industrial style is a bit longer. Both consist out of a two parts, male and female. When connected hardened balls or pins within the plug, keep the coupling tightly sealed and together. To connect or release the connection, one needs to pull back on the sling sleeve to release the locking balls. One of the major advantages of this type of connection is that an automatic seal off valve, when disconnected, eliminates the need for a separate shutoff. Another positive is that it allows for swivelling, preventing the hose from twisting.


Most air hose fittings are made out of brass, steel or stainless steel. It is relatively maintenance free but special care should be taken to connect each fitting properly as this might result in damage to the fitting or even equipment if not done correctly.

You may from time to time, want to check the rubber seals within the fittings, if applicable. It may become worn and should then be replaced. The hose itself should also be checked regularly for leaks.

Final Thought

Air pressure to pneumatic tools is what electricity is to electrical equipment. Certain standards need to be maintained. To ensure sufficient and constant airflow for tools to perform at optimal level, special thought should be given to the type and size of fittings used.