An apparatus for producing blow-moulded plastics products comprises an extrusion head 1 having two flow ducts 3a,3b which can each be connected to a respective source for feeding liquefied plastics material under pressure through a respective duct to and out through coaxial tube- forming nozzles 4a,4b which are connected to the outlet ends of the ducts and to a common annular outlet gap 5 for forming the plastics material into a ductile tube which can be inflated in a mould. Two adjacent coaxial nozzle ducts 4a,4b are radially delimited by means of three cylindrical, mutually separated coaxial wall faces of three duct-demarcating members 17,20,21, of which one member 20 demarcates the two nozzle ducts from each other. At least two of these duct-demarcating members 17,20,21 are arranged such that they are axially displaceable independently of one other and are configured such that the outlet dimensions of the nozzle ducts 4a,4b are adjustable independently of each other. IMAGE
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