Abstract: A packing element is provided for use in a mass transfer tower or a heat sink. The packing element is in the form of a saddle shaped member having a configuration generally corresponding to a portion of a toroid generated by rotating a plane closed curve about an axis that is coplanar with and spaced from the curve. The curve has inner and outer surface generating segments. The inner segment is closer to the axis than the outer segment. The outer segment is essentially w-shaped. The member has respective inner and outer surface portions which correspond in transverse cross-sectional shape to the shape of said segments. In one form of the invention, the inner segment is essentially w-shaped and complementary to said outer segment, whereby the element itself is essentially w-shaped in transverse cross-sectional configuration.