Foster QD 1/4in Male Quick Disconnect X 1/4" Fip
This is the standard industrial quick disconnect used by carpet cleaners.
Foster K2B has 1/4" female pipe threads and conforms with ISO Standard 7241-1, Series B (brass).
Spring loaded plug in tip keeps water from dripping out of end while you set up or wrap up your hoses.
Compare to current or past OEM Associations:
White Magic B001
Production Metal Forming QD40
Blue Baron QCM4