This wraps the ObjectARX AcDbAssocEdgeFilletActionBody class.

Autodesk.AutoCAD.DatabaseServices.DBObject
    Autodesk.AutoCAD.DatabaseServices.AssocActionBody
        Autodesk.AutoCAD.DatabaseServices.AssocParamBasedActionBody
            Autodesk.AutoCAD.DatabaseServices.AssocSurfaceActionBody
                Autodesk.AutoCAD.DatabaseServices.AssocEdgeFilletActionBody

Public Class AssocEdgeFilletActionBody
Inherits AssocSurfaceActionBody

public class AssocEdgeFilletActionBody : AssocSurfaceActionBody;