diff --git a/DDCore/include/DDSegmentation/CylindricalGridPhiZ.h b/DDCore/include/DDSegmentation/CylindricalGridPhiZ.h
index a02d01d47..54a836934 100644
--- a/DDCore/include/DDSegmentation/CylindricalGridPhiZ.h
+++ b/DDCore/include/DDSegmentation/CylindricalGridPhiZ.h
@@ -94,12 +94,12 @@ namespace dd4hep {
         _zId = fieldName;
       }
       /** \brief Returns a vector<double> of the cellDimensions of the given cell ID
-          in natural order of dimensions, e.g., dx/dy/dz, or dr/r*dPhi
+          in the following order: R*dPhi,dZ
 
           Returns a vector of the cellDimensions of the given cell ID
           \param cellID is ignored as all cells have the same dimension
           \return std::vector<double> size 2:
-          -# size in x
+          -# size in x = R * size in phi
           -# size in z
       */
       virtual std::vector<double> cellDimensions(const CellID& cellID) const;