Results are presented of total reflux distillation experiments carried out with Montz-Pak B1-350MN in a 1.22 m internal diameter column at Fractionation Research Inc. using two tests systems at two operating pressures, i.e. cyclohexane/n-heptane, at 0.31 and 1.62 bar, and paraxylene/orthoxylene at 0.1 and 1 bar, respectively. In all cases an impressive packing efficiency was achieved, ranging from five stages- at low to four stages per unit bed height at high vapour loads. Comparison with data obtained earlier with B1-250MN under similar conditions indicates a relatively higher maximum useful capacity of B1-350MN, while the relative efficiency and pressure drop are close to the ratio of installed specific geometric areas. The Delft model captures observed packing geometry related effects quite well qualitatively. Quantitatively, the efficiency and pressure drop predictions are on the safe side. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.