The results of mass transfer and hydrodynamic investigations on new random 1 " and 2 " packing McPac has been presented. Investigations were carried out in columns from 180 mm to 1600 mm in diameter using following systems: air-water, ammonia-air-water under atmospheric pressure and rectification systems: chlorebenzene-ethylbenzene under the pressure of 266 and 530 mbar, ethanol-water under normal pressure p = 1 bar and for total reflux. Comparison of the results for 1 " and 2 " McPac rings and the results of investigations on 25, 35 and 58-mm metal Pall rings was made.