diff --git a/Controller.php b/Controller.php
index a45c173..39fa3f4 100644
--- a/Controller.php
+++ b/Controller.php
@@ -38,7 +38,7 @@ use phpOMS\Message\Http\RequestStatusCode;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class Controller extends ModuleAbstract implements WebInterface
+final class Controller extends ModuleAbstract implements WebInterface
 {
 
     /**
diff --git a/Models/NullCalendar.php b/Models/NullCalendar.php
index 35a3d32..101d4dc 100644
--- a/Models/NullCalendar.php
+++ b/Models/NullCalendar.php
@@ -22,7 +22,7 @@ namespace Modules\Calendar\Models;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class NullCalendar extends Calendar
+final class NullCalendar extends Calendar
 {
 
 }
diff --git a/Models/NullEvent.php b/Models/NullEvent.php
index 9705869..63e67f2 100644
--- a/Models/NullEvent.php
+++ b/Models/NullEvent.php
@@ -22,7 +22,7 @@ namespace Modules\Calendar\Models;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class NullEvent extends Event
+final class NullEvent extends Event
 {
 
 }
diff --git a/Models/NullSchedule.php b/Models/NullSchedule.php
index b090a40..907e0df 100644
--- a/Models/NullSchedule.php
+++ b/Models/NullSchedule.php
@@ -22,6 +22,6 @@ namespace Modules\Calendar\Models;
  * @link       http://website.orange-management.de
  * @since      1.0.0
  */
-class NullSchedule extends Schedule
+final class NullSchedule extends Schedule
 {
 }