Koolance QD3-FSG4-BK QD3 Female Quick Disconnect No-Spill Coupling, Male Threaded G 1/4 BSPPBlack Koolance patented quick disconnect no-spill coupling with automatic shutoff. G 1/4 BSPP (parallel) thread female fitting for screwing directly into a water block or other component. It will only fit a Koolance QD3 male 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.