A method of manufacturing a variable crimped web material is provided, including feeding a substantially continuous web material; crimping a first region of the material at a first crimp value; and crimping a second region of the material, adjacent the first region, at a second crimp value, the crimping using a set of two rollers, each being corrugated across at least a portion of its width and corrugated around its circumference, and being configured so the corrugations across the width interleave with each other to crimp the material, so the troughs of the corrugations around the circumference crimp the material at the first crimp value, and so the peaks of the corrugations around the circumference crimp the material at the second crimp value. An apparatus for manufacturing a crimped web material, and a method of manufacturing air flow directing elements for smoking articles are also provided.