Katapak(R)-S-* is a structured catalytic packing for reactive distillation or gas-liquid reactors available from laboratory to industrial scale. Results of experimental studies of the flow regime, liquid hold-up, pressure drop, residence time behavior and separation efficiency of the laboratory Katapak(R)-S are reported. Two basic flow regimes in Katapak(R)-S can be distinguished: a) liquid loads up to the load point, where the liquid flows mainly inside the packing structure and b) liquid loads above the load point, where there is a liquid bypass on the outer surface of the structure. A model for predicting the flow regime in Katapak(R)-S is presented and successfully compared to experimental data. Furthermore, a model for predicting the pressure drop and liquid hold-up of Katapak(R)-S accounting for the different flow-regimes is developed. Again, a comparison to the experimental data shows good agreement. Finally, experimental results for the residence time behavior and separation efficiency of Katapak(R)-S are presented and discussed.