A structured packing module comprising: a plurality of structured packing sheets positioned in an upright, parallel relationship to each other, each structured packing sheet having corrugations formed of alternating peaks and valleys and corrugation sidewalls that extend between adjacent ones of the peaks and valleys , the structured packing sheets being constructed and arranged such that the corrugations of each one of the structured packing sheets extend at an oblique angle to the corrugations of each adjacent one of the structured packing sheets and a specific surface area of the structured packing sheets in the structured packing module is greater than 100 m 2 /m 3 ; and a plurality of apertures in the structured packing sheets for allowing passage of fluid through the structured packing sheets , the apertures in each one of the structured packing sheets being open to each adjacent one of the structured packing sheets and being substantially unimpeded, the apertures being distributed in each one of the structured packing sheets such that the corrugation sidewalls have a greater density of open areas formed by the apertures than any density of any of the open areas that may be present in the peaks and valleys , characterized in that said apertures are distributed such that a greater density of said open areas is present nearer the center lines of said corrugation sidewalls than any density of any open areas that may be present nearer to said peaks and valleys and in that the structured packing module includes spacers on said peaks that contact only some of the peaks on the facing side of an adjacent one of the structured packing sheets . a plurality of structured packing sheets positioned in an upright, parallel relationship to each other, each structured packing sheet having corrugations formed of alternating peaks and valleys and corrugation sidewalls that extend between adjacent ones of the peaks and valleys , the structured packing sheets being constructed and arranged such that the corrugations of each one of the structured packing sheets extend at an oblique angle to the corrugations of each adjacent one of the structured packing sheets and a specific surface area of the structured packing sheets in the structured packing module is greater than 100 m 2 /m 3 ; and a plurality of apertures in the structured packing sheets for allowing passage of fluid through the structured packing sheets , the apertures in each one of the structured packing sheets being open to each adjacent one of the structured packing sheets and being substantially unimpeded, the apertures being distributed in each one of the structured packing sheets such that the corrugation sidewalls have a greater density of open areas formed by the apertures than any density of any of the open areas that may be present in the peaks and valleys , characterized in that said apertures are distributed such that a greater density of said open areas is present nearer the center lines of said corrugation sidewalls than any density of any open areas that may be present nearer to said peaks and valleys and in that the structured packing module includes spacers on said peaks that contact only some of the peaks on the facing side of an adjacent one of the structured packing sheets . <EOS>