An extrusion head comprising at least one fixed head portion and at least one displaceable head portion pivotable into and out of an operative position includes means for filtering material being extruded and means for effecting change-over of the filter. The means for effecting the change-over includes at least two perforated plates displaceable on guide means in a direction generally at right angles to that of the extruded material. The at least one pivotable head portion includes a pressure surface which, in the operative position, abuts against the perforated plates thereby retaining the plates in position and sealing them against leakage of the extruded material.