Your average Sanke D coupler, but modified with MFL tailpieces so it can be attached to FFL swivel nuts (click here to see) on the end of hoses. Most commonly done to connect multiple types of couplers or homebrew disconnects (ball lock, pin lock, Sanke D and other European couplers) to a system without having to cut the lines, or fiddle with a worm clamp each time. See video below to see how this works or click here.
WARNING: This product can expose you to Cadmium, which is known to the state of California to cause cancer, birth defects and other reproductive harm. For more information go to: www.P65Warnings.ca.gov.