Standard BS terminal units are those points, fixed or flying, of a medical gas distribution system on which the user makes frequent connections and detachments to draw the various gases intended to supply anesthesia, ventilation, and general medical use equipment. Because incorrect connection can endanger the patient’s life, it is important that terminal units and their components are installed securely. Materials used: chrome-plated CW614N brass for the body and other parts, chrome-plated aluminum for the outer ferrule, stainless steel for the pins, C98 steel for the springs, and NBR or food-grade VITON rubber for the seals. All DIN terminal units possess on the base a dispensing block system with manual activation.