A device for making a profiled insulation having an extrusion die with an extrusion tip and a polymer chamber surrounding the extrusion tip. The polymer chamber has at least one air chamber therein. The air chamber is held in place and coupled to the outside of the extrusion die by a vertical fin extending outwards from the extrusion tip. When molten polymer flows through the polymer chamber around the air chamber, an opening is introduced into the polymer such that the profiled insulation is formed as the polymer exits the extrusion die, having a longitudinal cavity therein corresponding to the location of the opening formed by the at least one air chamber.