This type of liquid distributor has long been the primary device selected for standard performance random packing where liquid flow rates are moderate to high levels. These styles of liquid distributors consist of a perforated deck with holes or drip tubes for the liquid and round or rectangular risers for the vapor. O/R distributors with holes in the floor generally attain at least a 2:1 turndown range for liquid distribution. To achieve higher turndown ranges, such as 10:1, the holes are replaced with drip tubes with multiple levels of holes. The O/R distributors with drip tubes are also used in moderate fouling systems since they provide a zone for solids to settle out away from the distribution holes. The O/R type distributor is also a good re-distributor with the addition of riser hats.