Abstract: There is disclosed an improved mass transfer or gas-liquid contact device having a specially contoured grid member(s) interposed in the gas flow of the device. Ideally the grid member(s) has a cross-sectional profile which equals the sum of the theoretical velocity pressure profile of the gas flowing in an open vessel and the static and dynamic heads of the contacting liquid. An additional depth is added to the grid approximately 5 to 40% more, to create an energy imbalance in favor of the introduced liquid, thereby allowing it to drain. In existing vessels where it is desirable to replace prior art devices with an apparatus embodying the present invention, a plurality of grid modules may be employed, each module including a shaped grid or grid pair approximating the velocity profile of the gas stream in each.