The extruded hollow profile has at least one axial inner wall (5). The open end of the profile is fitted with a press-fit plastics moulded cap (2) which has piston-shaped inner seals (8) for the hollow profile attached to the underside of the cap by rigid rods (7). The cap has a hole (9) to inject the space between the cap and the seals with a sealing compound (11).The cap has a vent hole (10) away from the filler hole. The sealing compound flows over the outer edge of the axial wall via a recess (13) in the cap. The operator injects the sealing compound until excess compound is vented out of the vent hole.
