diff --git a/corsika/setup/SetupEnvironment.hpp b/corsika/setup/SetupEnvironment.hpp
index b7f59b31b6aa34d914206285f37463ce4981cb37..831cf3f6b310e1e2135384a50b0b9cd56d4f2b86 100644
--- a/corsika/setup/SetupEnvironment.hpp
+++ b/corsika/setup/SetupEnvironment.hpp
@@ -22,7 +22,8 @@ namespace corsika::setup {
      bdependent way.
    */
 
-  using EnvironmentInterface = IMediumPropertyModel<IMagneticFieldModel<IMediumModel>>;
+  using EnvironmentInterface =
+      IRefractiveIndexModel<IMediumPropertyModel<IMagneticFieldModel<IMediumModel>>>;
   using Environment = Environment<EnvironmentInterface>;
 
 } // end namespace corsika::setup