Quick ConnectorDk-Lok brings you excellent quality Outstanding customer service and availability Enjoy Dk-Lok tube fitting working your application ! DQ Series Quick ConnectorsDQ, DQM, and DF Series Catalog 2D / 3D Spec. Bi-directional flow design Simple to operate SS316 construction with standard FKM O-ring Brass construction with standard NBR O-ring Compact and light-weight design Brief Description No tools required to couple to uncouple. Bi-directional flow design Versatile options of both-end shutoff, single-end shutoff Key Type Prevent intermixing of different keys mechanically as well as allow visual identification by color coding. Eight (8) different keys on each DQ series are available with its own Key number. DQ keys are useful to control multi-fluid or multi- pressure systems.