diff --git a/cura/Machines/Models/BaseMaterialsModel.py b/cura/Machines/Models/BaseMaterialsModel.py
index c93473031a..de0c68d60a 100644
--- a/cura/Machines/Models/BaseMaterialsModel.py
+++ b/cura/Machines/Models/BaseMaterialsModel.py
@@ -6,6 +6,12 @@ from PyQt5.QtCore import Qt, pyqtSignal, pyqtProperty
 from UM.Qt.ListModel import ListModel
 
 
+#
+# This is the base model class for GenericMaterialsModel and BrandMaterialsModel
+# Those 2 models are used by the material drop down menu to show generic materials and branded materials separately.
+# The extruder position defined here is being used to bound a menu to the correct extruder. This is used in the top
+# bar menu "Settings" -> "Extruder nr" -> "Material" -> this menu
+#
 class BaseMaterialsModel(ListModel):
     RootMaterialIdRole = Qt.UserRole + 1
     IdRole = Qt.UserRole + 2