Abstract: A corrugated strip made of sheet material, which may be used in a packing module. The peaks and the troughs of the strip, when viewed in a side view, define lines which have a general sloping direction relative to the direction the fluid flow. Each strip includes a spanning zone and a transition zone. In the transition zone, each peak/trough line extends inside a specific area centered on a curve which extends tangentially from the peak/trough line of the spanning zone. The structured interface region between the spanning and transition zones helps to reduce head loss across the strip.