Gravity FASTARC range of cutting nozzles utilizes the nozzle mixing principle whereby the fuel gas and oxygen are kept separate right upto the nozzle and are only mixed once inside the preheat orifices . Acetylene nozzles called ANME are manufactured from solid copper and are one piece design whereas Fuel gas nozzles called PNME are to piece design made up of brass inner with splines and a hollow cooper outer cover