Koolance QD4-FS13X19-BK QD4 Female Quick Disconnect No-Spill Coupling, Compression for 13mm x 19mm (1/2in x 3/4in) *Black* Koolance patented quick disconnect no-spill coupling with automatic shutoff. 13mm (1/2in) ID, 19mm (3/4in) OD female straight connection with compression fitting. It will only fit a Koolance QD4 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.