Koolance (patent-pending) quick-disconnect no-spill shutoff valve. 13mm (1/2") ID, 19mm (3/4") OD (common Tygon tubing size) female straight connection with compression fitting. It will only fit any Koolance VL3N male shutoff valve.After a quarter twist, the quick-disconnect nozzles will separate. Liquid on both sides will be automatically obstructed with only 0.5-1mL freed with only 0.2mL freed. Nozzles are nickel-plated brass.