MTM Hydro's M22 Twist Seal Coupler X QC Fittings bring the best of the European market and the demands of the U.S market into a single joint. M22 fittings were developed as the original high pressure fitting for the European market where they are still used today. These M22 style fittings may not be fast but are now widely used in the residential market as a safe and secure way to provide a consistent method for attaching and detaching fittings. When paired with the standard QC fittings in U.S. this reliable fitting is now faster than ever when swapping accessories.
When purchasing M22 fittings, the black portion is considered the Coupler. The brass exposed threads are considered the Plug and is meant to thread into the black coupler.
 
Terminology may vary when referencing M22s among suppliers. MTM Hydro nomenclature refers to the black twist coupler portion as "M22F" while the plugs are referred to as "M22M" followed by the sizing of the secondary end as NPT or other Variant of M22. MTM Hydro M22 manufacturing materials are offered in both brass and plated steel depending upon the item. See image for clarification.