diff --git a/DDG4/src/Geant4ShapeConverter.cpp b/DDG4/src/Geant4ShapeConverter.cpp
index 81e87147416939ead2dc7199153d51ba47a740af..0023c3d7df4fe8e57116af6b3e381b09ffd03695 100644
--- a/DDG4/src/Geant4ShapeConverter.cpp
+++ b/DDG4/src/Geant4ShapeConverter.cpp
@@ -109,7 +109,7 @@ namespace dd4hep {
       if ( std::fabs(std::fabs(sh->GetNegativeEndZ()) - std::fabs(sh->GetPositiveEndZ())) < 1e-10 )   {
         return new G4TwistedTubs(sh->GetName(),sh->GetPhiTwist() * DEGREE_2_RAD,
                                  sh->GetRmin() * CM_2_MM, sh->GetRmax() * CM_2_MM,
-                                 sh->GetNegativeEndZ() * CM_2_MM,
+                                 sh->GetPositiveEndZ() * CM_2_MM,
                                  sh->GetNsegments(),
                                  (sh->GetPhi2()-sh->GetPhi1()) * DEGREE_2_RAD);
       }