These are used in a different way for water extraction. Technical Specifications for Finolex Screen Pipes with Ribs Nominal Diameter DN (mm)Mean Outside Diameter of PipeOutside Diameter of Pipe at Any PointMean Outside Diameter Over ConnectionWall Thickness t (mm) Cat No.Package L MinMaxMinMinMax405251.9563.54 506463.96944.6 809291.89844.6 100117116.812455.710201009931023 mtr150168168.61827.58.510201509931003 mtr200229228.52471011.210202009931003 mtr