INCLUDING – Supplied with 1 female fitting with thread and 1 female fitting with thread and 4 male fitting, male fitting and 4 female fitting, male fitting. For pneumatic tools, air compressors, air hose set. FUNCTION – Spring-loaded quick couplers for use on the compressor side have a built-in valve to shut off air when switching between tools. Nickel plated finish for rust and corrosion resistance. SIZE – 1/4 BSP. 12 mm hex clamp (male fitting) 16 mm hex clamp (male fitting) 19 mm hex clamp (female / male fitting) Type: Male / female fitting, male / female thread. DESIGN – Simple to use, just slide the collar back and insert the fitting, then slide the collar all the way back to lock it in place. Allows tools and airlines to be quickly connected/disconnected. ADVANTAGE – Made from hardened heat treated steel. Spring loaded quick couplers for compressor side use have an integrated valve to prevent air from escaping when changing tools.