diff --git a/src/Mod/Fem/App/FemConstraintSpring.cpp b/src/Mod/Fem/App/FemConstraintSpring.cpp
index b8fe3d1194..87b44a5b03 100644
--- a/src/Mod/Fem/App/FemConstraintSpring.cpp
+++ b/src/Mod/Fem/App/FemConstraintSpring.cpp
@@ -26,25 +26,31 @@
 #include "FemConstraintSpring.h"
 
 
+static const char* Stiffnesses[] = {"Normal Stiffness",
+                                    "Tangential Stiffness", nullptr};
+
 using namespace Fem;
 
 PROPERTY_SOURCE(Fem::ConstraintSpring, Fem::Constraint)
 
 ConstraintSpring::ConstraintSpring()
 {
-    ADD_PROPERTY(normalStiffness,(0.0));
-    ADD_PROPERTY(tangentialStiffness,(0.0));
-    ADD_PROPERTY_TYPE(Points,(Base::Vector3d()),"ConstraintSpring",
-        App::PropertyType(App::Prop_ReadOnly|App::Prop_Output),
+    ADD_PROPERTY(NormalStiffness, (0.0));
+    ADD_PROPERTY(TangentialStiffness, (0.0));
+    ADD_PROPERTY(ElmerStiffness, (1));
+    ADD_PROPERTY_TYPE(Points, (Base::Vector3d()), "ConstraintSpring",
+        App::PropertyType(App::Prop_ReadOnly | App::Prop_Output),
         "Points where arrows are drawn");
-    ADD_PROPERTY_TYPE(Normals,(Base::Vector3d()),"ConstraintSpring",
-        App::PropertyType(App::Prop_ReadOnly|App::Prop_Output),
+    ADD_PROPERTY_TYPE(Normals, (Base::Vector3d()), "ConstraintSpring",
+        App::PropertyType(App::Prop_ReadOnly | App::Prop_Output),
         "Normals where symbols are drawn");
+
+    ElmerStiffness.setEnums(Stiffnesses);
     Points.setValues(std::vector<Base::Vector3d>());
     Normals.setValues(std::vector<Base::Vector3d>());
 }
 
-App::DocumentObjectExecReturn *ConstraintSpring::execute()
+App::DocumentObjectExecReturn* ConstraintSpring::execute()
 {
     return Constraint::execute();
 }
diff --git a/src/Mod/Fem/App/FemConstraintSpring.h b/src/Mod/Fem/App/FemConstraintSpring.h
index 36d0fd8344..bc6fd144bd 100644
--- a/src/Mod/Fem/App/FemConstraintSpring.h
+++ b/src/Mod/Fem/App/FemConstraintSpring.h
@@ -36,8 +36,9 @@ class FemExport ConstraintSpring : public Fem::Constraint
 public:
     ConstraintSpring();
 
-    App::PropertyFloat normalStiffness;
-    App::PropertyFloat tangentialStiffness;
+    App::PropertyStiffness NormalStiffness;
+    App::PropertyStiffness TangentialStiffness;
+    App::PropertyEnumeration ElmerStiffness;
     App::PropertyVectorList Points;
     App::PropertyVectorList Normals;
 
diff --git a/src/Mod/Fem/Gui/Command.cpp b/src/Mod/Fem/Gui/Command.cpp
index 2ad7e33c3b..6776b7f5bb 100644
--- a/src/Mod/Fem/Gui/Command.cpp
+++ b/src/Mod/Fem/Gui/Command.cpp
@@ -854,10 +854,10 @@ void CmdFemConstraintSpring::activated(int)
     doCommand(
         Doc, "App.activeDocument().addObject(\"Fem::ConstraintSpring\",\"%s\")", FeatName.c_str());
     doCommand(Doc,
-              "App.activeDocument().%s.normalStiffness = 1.0",
+              "App.activeDocument().%s.NormalStiffness = 1.0",
               FeatName.c_str());//OvG: set default not equal to 0
     doCommand(Doc,
-              "App.activeDocument().%s.tangentialStiffness = 0.0",
+              "App.activeDocument().%s.TangentialStiffness = 0.0",
               FeatName.c_str());//OvG: set default to False
     doCommand(
         Doc, "App.activeDocument().%s.Scale = 1", FeatName.c_str());//OvG: set initial scale to 1
diff --git a/src/Mod/Fem/Gui/TaskFemConstraintDisplacement.cpp b/src/Mod/Fem/Gui/TaskFemConstraintDisplacement.cpp
index e206c141f6..a8eeeee6cc 100644
--- a/src/Mod/Fem/Gui/TaskFemConstraintDisplacement.cpp
+++ b/src/Mod/Fem/Gui/TaskFemConstraintDisplacement.cpp
@@ -489,7 +489,6 @@ std::string TaskFemConstraintDisplacement::get_zFormula() const
     QString zFormula = ui->DisplacementZFormulaLE->text();
     zFormula.replace(QString::fromLatin1("\""), QString::fromLatin1("\\\""));
     return zFormula.toStdString();
-    ;
 }
 
 bool TaskFemConstraintDisplacement::get_dispxfix() const
diff --git a/src/Mod/Fem/Gui/TaskFemConstraintFluidBoundary.cpp b/src/Mod/Fem/Gui/TaskFemConstraintFluidBoundary.cpp
index 3ca57be3d1..fce826cd97 100644
--- a/src/Mod/Fem/Gui/TaskFemConstraintFluidBoundary.cpp
+++ b/src/Mod/Fem/Gui/TaskFemConstraintFluidBoundary.cpp
@@ -114,11 +114,8 @@ void initComboBox(QComboBox* combo, const std::vector<std::string>& textItems,
     combo->clear();
     for (unsigned int it = 0; it < textItems.size(); it++) {
         combo->insertItem(it, Base::Tools::fromStdString(textItems[it]));
-        if (sItem == textItems[it]) {
+        if (sItem == textItems[it])
             iItem = it;
-            // Base::Console().Warning("Found the subtype and set the current index as %d for
-            // subtype %s ComboBox\n", it, sItem);
-        }
     }
     combo->setCurrentIndex(iItem);
     combo->blockSignals(false);
diff --git a/src/Mod/Fem/Gui/TaskFemConstraintSpring.cpp b/src/Mod/Fem/Gui/TaskFemConstraintSpring.cpp
index 87da58045b..80f31eda1d 100644
--- a/src/Mod/Fem/Gui/TaskFemConstraintSpring.cpp
+++ b/src/Mod/Fem/Gui/TaskFemConstraintSpring.cpp
@@ -29,6 +29,7 @@
 # include <sstream>
 #endif
 
+#include <Base/Tools.h>
 #include <Gui/Command.h>
 #include <Gui/SelectionObject.h>
 #include <Mod/Fem/App/FemConstraintSpring.h>
@@ -71,22 +72,30 @@ TaskFemConstraintSpring::TaskFemConstraintSpring(ViewProviderFemConstraintSpring
     std::vector<std::string> SubElements = pcConstraint->References.getSubValues();
 
     // Fill data into dialog elements
+    ui->if_norm->setUnit(pcConstraint->NormalStiffness.getUnit());
     ui->if_norm->setMinimum(
         0);// TODO fix this -------------------------------------------------------------------
     ui->if_norm->setMaximum(FLOAT_MAX);
     Base::Quantity ns =
-        Base::Quantity((pcConstraint->normalStiffness.getValue()), Base::Unit::Stiffness);
+        Base::Quantity((pcConstraint->NormalStiffness.getValue()), Base::Unit::Stiffness);
     ui->if_norm->setValue(ns);
 
-    // Fill data into dialog elements
+    ui->if_tan->setUnit(pcConstraint->TangentialStiffness.getUnit());
     ui->if_tan->setMinimum(
         0);// TODO fix this -------------------------------------------------------------------
     ui->if_tan->setMaximum(FLOAT_MAX);
     Base::Quantity ts =
-        Base::Quantity((pcConstraint->tangentialStiffness.getValue()), Base::Unit::Stiffness);
+        Base::Quantity((pcConstraint->TangentialStiffness.getValue()), Base::Unit::Stiffness);
     ui->if_tan->setValue(ts);
 
-    /* */
+    ui->ElmerStiffnessCB->clear();
+    auto stiffnesses = pcConstraint->ElmerStiffness.getEnumVector();
+    QStringList stiffnessesList;
+    for (auto item : stiffnesses) {
+        stiffnessesList << QLatin1String(item.c_str());
+    }
+    ui->ElmerStiffnessCB->addItems(stiffnessesList);
+    ui->ElmerStiffnessCB->setCurrentIndex(pcConstraint->ElmerStiffness.getValue());
 
     ui->lw_references->clear();
     for (std::size_t i = 0; i < Objects.size(); i++) {
@@ -96,7 +105,7 @@ TaskFemConstraintSpring::TaskFemConstraintSpring(ViewProviderFemConstraintSpring
         ui->lw_references->setCurrentRow(0, QItemSelectionModel::ClearAndSelect);
     }
 
-    //Selection buttons
+    // Selection buttons
     buttonGroup->addButton(ui->btnAdd, (int)SelectionChangeModes::refAdd);
     buttonGroup->addButton(ui->btnRemove, (int)SelectionChangeModes::refRemove);
 
@@ -245,21 +254,20 @@ const std::string TaskFemConstraintSpring::getReferences() const
     return TaskFemConstraint::getReferences(items);
 }
 
-/* Note: */
-double TaskFemConstraintSpring::get_normalStiffness() const
+std::string TaskFemConstraintSpring::get_normalStiffness() const
 {
-    Base::Quantity stiffness = ui->if_norm->getQuantity();
-    double stiffness_double = stiffness.getValueAs(Base::Quantity::NewtonPerMeter);
-    return stiffness_double;
+    return ui->if_norm->value().getSafeUserString().toStdString();
 }
 
-double TaskFemConstraintSpring::get_tangentialStiffness() const
+std::string TaskFemConstraintSpring::get_tangentialStiffness() const
 {
-    Base::Quantity stiffness = ui->if_tan->getQuantity();
-    double stiffness_double = stiffness.getValueAs(Base::Quantity::NewtonPerMeter);
-    return stiffness_double;
+    return ui->if_tan->value().getSafeUserString().toStdString();
 }
 
+std::string TaskFemConstraintSpring::getElmerStiffness() const
+{
+    return Base::Tools::toStdString(ui->ElmerStiffnessCB->currentText());
+}
 
 bool TaskFemConstraintSpring::event(QEvent* e)
 {
@@ -320,13 +328,17 @@ bool TaskDlgFemConstraintSpring::accept()
 
     try {
         Gui::Command::doCommand(Gui::Command::Doc,
-                                "App.ActiveDocument.%s.normalStiffness = %f",
+                                "App.ActiveDocument.%s.NormalStiffness = \"%s\"",
                                 name.c_str(),
-                                parameterStiffness->get_normalStiffness());
+                                parameterStiffness->get_normalStiffness().c_str());
         Gui::Command::doCommand(Gui::Command::Doc,
-                                "App.ActiveDocument.%s.tangentialStiffness = %f",
+                                "App.ActiveDocument.%s.TangentialStiffness = \"%s\"",
                                 name.c_str(),
-                                parameterStiffness->get_tangentialStiffness());
+                                parameterStiffness->get_tangentialStiffness().c_str());
+        Gui::Command::doCommand(Gui::Command::Doc,
+                                "App.ActiveDocument.%s.ElmerStiffness = '%s'",
+                                name.c_str(),
+                                parameterStiffness->getElmerStiffness().c_str());
         std::string scale = parameterStiffness->getScale();// OvG: determine modified scale
         Gui::Command::doCommand(Gui::Command::Doc,
                                 "App.ActiveDocument.%s.Scale = %s",
diff --git a/src/Mod/Fem/Gui/TaskFemConstraintSpring.h b/src/Mod/Fem/Gui/TaskFemConstraintSpring.h
index e26975de28..2bd95d68d2 100644
--- a/src/Mod/Fem/Gui/TaskFemConstraintSpring.h
+++ b/src/Mod/Fem/Gui/TaskFemConstraintSpring.h
@@ -43,8 +43,9 @@ public:
                                      QWidget* parent = nullptr);
     ~TaskFemConstraintSpring() override;
     const std::string getReferences() const override;
-    double get_normalStiffness()const;
-    double get_tangentialStiffness()const;
+    std::string get_normalStiffness() const;
+    std::string get_tangentialStiffness() const;
+    std::string getElmerStiffness() const;
 
 private Q_SLOTS:
     void onReferenceDeleted();
diff --git a/src/Mod/Fem/Gui/TaskFemConstraintSpring.ui b/src/Mod/Fem/Gui/TaskFemConstraintSpring.ui
index 467e6eec29..14160ec9a6 100644
--- a/src/Mod/Fem/Gui/TaskFemConstraintSpring.ui
+++ b/src/Mod/Fem/Gui/TaskFemConstraintSpring.ui
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>300</width>
-    <height>191</height>
+    <height>217</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -59,40 +59,17 @@
    </item>
    <item>
     <widget class="QListWidget" name="lw_references">
-     <property name="sizePolicy">
-      <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
-       <horstretch>0</horstretch>
-       <verstretch>0</verstretch>
-      </sizepolicy>
-     </property>
-     <property name="baseSize">
+     <property name="maximumSize">
       <size>
-       <width>0</width>
-       <height>0</height>
+       <width>16777215</width>
+       <height>75</height>
       </size>
      </property>
     </widget>
    </item>
    <item>
     <layout class="QGridLayout" name="gridLayout_2">
-     <item row="0" column="0">
-      <widget class="QLabel" name="label_1">
-       <property name="text">
-        <string>Normal Stiffness</string>
-       </property>
-      </widget>
-     </item>
-     <item row="0" column="1">
-      <widget class="Gui::InputField" name="if_norm">
-       <property name="text">
-        <string notr="true">0 </string>
-       </property>
-       <property name="unit" stdset="0">
-        <string notr="true"/>
-       </property>
-      </widget>
-     </item>
-     <item row="1" column="0">
+     <item row="2" column="0">
       <widget class="QLabel" name="label_2">
        <property name="sizePolicy">
         <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
@@ -105,28 +82,51 @@
        </property>
       </widget>
      </item>
-     <item row="1" column="1">
-      <widget class="Gui::InputField" name="if_tan">
-       <property name="sizePolicy">
-        <sizepolicy hsizetype="Expanding" vsizetype="Fixed">
-         <horstretch>0</horstretch>
-         <verstretch>0</verstretch>
-        </sizepolicy>
-       </property>
+     <item row="2" column="1">
+      <widget class="Gui::QuantitySpinBox" name="if_tan">
        <property name="unit" stdset="0">
         <string notr="true"/>
        </property>
       </widget>
      </item>
+     <item row="0" column="0">
+      <widget class="QLabel" name="label_1">
+       <property name="text">
+        <string>Normal Stiffness</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <widget class="Gui::QuantitySpinBox" name="if_norm">
+       <property name="unit" stdset="0">
+        <string notr="true"/>
+       </property>
+      </widget>
+     </item>
+     <item row="3" column="0">
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>Stiffness for Elmer</string>
+       </property>
+      </widget>
+     </item>
+     <item row="3" column="1">
+      <widget class="QComboBox" name="ElmerStiffnessCB">
+       <property name="toolTip">
+        <string>What stiffness should be
+used for the Elmer solver</string>
+       </property>
+      </widget>
+     </item>
     </layout>
    </item>
   </layout>
  </widget>
  <customwidgets>
   <customwidget>
-   <class>Gui::InputField</class>
-   <extends>QLineEdit</extends>
-   <header>Gui/InputField.h</header>
+   <class>Gui::QuantitySpinBox</class>
+   <extends>QWidget</extends>
+   <header>Gui/QuantitySpinBox.h</header>
   </customwidget>
  </customwidgets>
  <resources/>
diff --git a/src/Mod/Fem/femexamples/equation_deformation_spring_elmer.py b/src/Mod/Fem/femexamples/equation_deformation_spring_elmer.py
index 7ec9240baf..a8cd2b29bf 100644
--- a/src/Mod/Fem/femexamples/equation_deformation_spring_elmer.py
+++ b/src/Mod/Fem/femexamples/equation_deformation_spring_elmer.py
@@ -41,7 +41,7 @@ def get_information():
         "name": "Deformation (nonlinear elasticity) - Elmer",
         "meshtype": "solid",
         "meshelement": "Tet10",
-        "constraints": ["displacement"],
+        "constraints": ["displacement", "spring"],
         "solvers": ["elmer"],
         "material": "solid",
         "equations": ["deformation"]
@@ -166,6 +166,19 @@ def setup(doc=None, solvertype="elmer"):
     DisplaceRight.References = [(SpringObject, "Face5")]
     analysis.addObject(DisplaceRight)
 
+    # constraints spring
+    StiffnessLeft = doc.addObject("Fem::ConstraintSpring", "StiffnessLeft")
+    StiffnessLeft.TangentialStiffness = "50 N/m"
+    StiffnessLeft.ElmerStiffness = "Tangential Stiffness"
+    StiffnessLeft.References = [(SpringObject, "Face1")]
+    analysis.addObject(StiffnessLeft)
+
+    StiffnessRight = doc.addObject("Fem::ConstraintSpring", "StiffnessRight")
+    StiffnessRight.TangentialStiffness = "50 N/m"
+    StiffnessRight.ElmerStiffness = "Tangential Stiffness"
+    StiffnessRight.References = [(SpringObject, "Face5")]
+    analysis.addObject(StiffnessRight)
+
     # mesh
     femmesh_obj = analysis.addObject(ObjectsFem.makeMeshGmsh(doc, get_meshname()))[0]
     femmesh_obj.Part = body
diff --git a/src/Mod/Fem/femsolver/elmer/equations/deformation_writer.py b/src/Mod/Fem/femsolver/elmer/equations/deformation_writer.py
index 10717cad56..39191256b9 100644
--- a/src/Mod/Fem/femsolver/elmer/equations/deformation_writer.py
+++ b/src/Mod/Fem/femsolver/elmer/equations/deformation_writer.py
@@ -130,6 +130,15 @@ class DeformationWriter:
                             displacement = obj.zDisplacementFormula
                         self.write.boundary(name, "Displacement 3", displacement)
                 self.write.handled(obj)
+        for obj in self.write.getMember("Fem::ConstraintSpring"):
+            if obj.References:
+                for name in obj.References[0][1]:
+                    if obj.ElmerStiffness == "Normal Stiffness":
+                        spring = float(obj.NormalStiffness.getValueAs("N/m"))
+                    else:
+                        spring = float(obj.TangentialStiffness.getValueAs("N/m"))
+                    self.write.boundary(name, "Spring", spring)
+                self.write.handled(obj)
 
     def handleDeformationInitial(self, bodies):
         pass
diff --git a/src/Mod/Fem/femsolver/elmer/equations/elasticity_writer.py b/src/Mod/Fem/femsolver/elmer/equations/elasticity_writer.py
index 1e931fe3c6..70c2de265f 100644
--- a/src/Mod/Fem/femsolver/elmer/equations/elasticity_writer.py
+++ b/src/Mod/Fem/femsolver/elmer/equations/elasticity_writer.py
@@ -346,6 +346,15 @@ class ElasticityWriter:
                             displacement = obj.zDisplacementFormula
                         self.write.boundary(name, "Displacement 3", displacement)
                 self.write.handled(obj)
+        for obj in self.write.getMember("Fem::ConstraintSpring"):
+            if obj.References:
+                for name in obj.References[0][1]:
+                    if obj.ElmerStiffness == "Normal Stiffness":
+                        spring = float(obj.NormalStiffness.getValueAs("N/m"))
+                    else:
+                        spring = float(obj.TangentialStiffness.getValueAs("N/m"))
+                    self.write.boundary(name, "Spring", spring)
+                self.write.handled(obj)
 
     def handleElasticityInitial(self, bodies):
         pass