Coextrusion refers to the simultaneously extrusion of multiple layers of material. This type of extrusion utilizes two or more extruders to melt and deliver a steady volumetric throughput of different molten plastics to a feedblock (“blackbox”), which combines the materials and transport the material to the die head, which molds the material into the desired shape. The different layers thickness are controlled by the relative speeds and sizes of the individual extruders delivering the materials.