The Axial scrubber is the modern scrubber in design. Axial scrubbers are most times used in two hose breathing loops, sometimes even with split counter lungs. There is a very old discussion on the efficiency of this scrubber type versus radial models. Only very complex tests show that the quantity of scrubber material, flow, form of the housing and many other factors determine the quality of a scrubber. Axial or Radial is not a general recipe for a  good or bad scrubber.

An axial scrubber is a scrubber design in which the breathing gases move from top to bottom (or vise-versa) through the scrubber. An example of a simple axial flow scrubber would be to start with a coffee can with a removable top. Punch holes in the top and bottom of the coffee can and fill the middle with soda lime then put the top on. Seal the entire unit into the breathing loop. In this example the gases must travel from one side of the can to the other. Contrast this with "Radial scrubber"

Beware: some scrubbers look of the axial type but are in fact a radial design. This can be misleading, although it won't hurt you when it is a good design! An example of this model is the azimuth scrubber.