Abstract: The invention relates to devices (50, 100) and a method for the coating of conductor lines, in particular for the insulation of stator windings of rotating electrical machines. According to the invention, an extruder head (50) is provided for use in a device for the coating of a conductor or a conductor line (72), having at least one extruder die (56), which is connected on one side to a supply conduit (58) for feeding the coating material. On the other side, the extruder die (56) opens out into into a region to which the conductor that is to be coated or the conductor line that is to be coated is adjacent during operation. Furthermore, the outlet of the extruder die (56) can be closed by means of a seal (57).