1 x Genuine Weber emulsion tube to suit DCOE, DCO/SP, IDF & 48 IDA carburettors. Will also suit Porsche PMO carburetors. Basic range of Emulsion tubes is;     LEAN:  F14, F11, F15, F16, F9, F2, F5, F8, F7 :RICH More high holes typically means a leaner mixture under slight accelerations, more low holes is richer. The thickness of the emulsion tube also has an impact on the amount of fuel sitting in the well surrounding the emulsion tubes. The Weber tuning manual has may pages dedicated to emulsion tubes with detailed drawings and measurements of the varying emulsion tubes. This is a genuine Weber (European) emulsion tube.