Koolance patented quick disconnect no-spill coupling with automatic shutoff. G 1/4 BSPP (parallel) thread female with panel-mount opposite a male "QD3" quick-disconnect. It will only fit a Koolance QD3 female quick disconnect.
After pulling the ring on the female QDC side, the quick-disconnect fittings will separate. Liquid on both sides will be automatically obstructed with approximately 0.2ml freed. Coolant volume lost upon disconnection will rise with internal pressure higher than 0.5kgf/cm2 (7psi). Fittings are nickel-plated brass, EPDM o-rings.