Koolance (patent-pending) quick-disconnect no-spill shutoff valve. 13mm (1/2") ID male straight connection with compression fitting. It will only fit any Koolance VL3N female shutoff valve.After a quarter twist, the quick-disconnect nozzles will separate. Liquid on both sides will be automatically obstructed with only 0.2mL freed. Nozzles are nickel-plated brass.