diff --git a/src/geant4_application/include/geant4_application/DataModel.h b/src/geant4_application/include/geant4_application/DataModel.h
index a5dba6c..335d3d5 100644
--- a/src/geant4_application/include/geant4_application/DataModel.h
+++ b/src/geant4_application/include/geant4_application/DataModel.h
@@ -150,7 +150,7 @@ struct Builders {
     StepPositionBuilder<double> step_position;
     StepMomentumBuilder<double> step_momentum;
 
-    Builders(const std::unordered_set<std::string>& fields) : fields(fields){};
+    Builders(const std::unordered_set<std::string>& fields) : fields(fields) {};
 };