The present invention relates to equipment/apparatus, and the relative method/process, for the treatment of synthetic filaments, in particular for drawing said filaments, comprising at least two nozzles each provided with a main passage, through which said yarns pass, having a section variable between an inlet portion and an outlet portion and into which at least one supply channel opens to supply a fluid according to a preferential direction. Advantageously, the nozzles are provided in line and the sections of the main passage of the second nozzle have an area at least 3% larger than the corresponding sections of the main passage of the first nozzle.