Abstract: An extrusion die for producing a fastener profile having a male profile portion and an alignment rib spaced on each side thereof has a first peripheral slot to produce the male profile portion and second and third slots to produce the ribs. By inclining the axes of the second and third slots relative to the first slot, preferably at respective different angles, one can remove the tendency for the male profile portion to tilt or roll and reduce lateral stresses set up during the extrusion process. The thermoplastic material is fed to each of the three slots separately, and preferably at a pressure to the second and third slots which is greater than to the first slot.