ADOPTED_FROM:ENV 737-6:2003 1.1 This part of this European standard specifies the dimensions and allocation of probes intended to be connected to terminal units of medical gas pipeline systems specified in EN 737-3 for use with the following medical gases: oxygen; nitrous oxide; air for breathing; carbon dioxide; oxygen/nitrous oxide mixture (50/50 % V/V ); nitric oxide/nitrogen mixture (NO 500 ul/l); air for driving surgical tools; nitrogen for driving surgical tools; vacuum.