diff --git a/k4Gen/src/components/HepMCFullMerge.h b/k4Gen/src/components/HepMCFullMerge.h
index 536e353..78684fb 100644
--- a/k4Gen/src/components/HepMCFullMerge.h
+++ b/k4Gen/src/components/HepMCFullMerge.h
@@ -15,7 +15,7 @@
  * Implementation partly due to pilemc https://pilemc.hepforge.org/
  */
 
-class HepMCFullMerge : public GaudiTool, virtual public IHepMCMergeTool {
+class HepMCFullMerge final: public GaudiTool, virtual public IHepMCMergeTool {
 public:
   HepMCFullMerge(const std::string& type, const std::string& name, const IInterface* parent);
 
diff --git a/k4Gen/src/components/HepMCSimpleMerge.h b/k4Gen/src/components/HepMCSimpleMerge.h
index c6c03b9..a7028c9 100644
--- a/k4Gen/src/components/HepMCSimpleMerge.h
+++ b/k4Gen/src/components/HepMCSimpleMerge.h
@@ -9,7 +9,7 @@
 #include "GaudiKernel/RndmGenerators.h"
 
 
-class HepMCSimpleMerge : public GaudiTool, virtual public IHepMCMergeTool {
+class HepMCSimpleMerge final: public GaudiTool, virtual public IHepMCMergeTool {
 public:
   HepMCSimpleMerge(const std::string& type, const std::string& name, const IInterface* parent);