Physical description
The McKesson Nargraf machine is affixed to a four-legged metal stand with castors. The head of the machine has two reduced pressure gauges on top: one each for oxygen and nitrous oxide. Below each pressure gauge is a cylindrical drum, where the green-painted faces are directed outwards. There is a pressure control valve with a dial on top of the machine between the two pressure gauges, and a large mixing valve in the centre of the machine head that regulates the proportions of oxygen and nitrous oxide. In front of the mixing valve is a glass cylinder with fabric threads hanging down from the top surface inside.