diff --git a/plugins/GCodeReader/FlavorParser.py b/plugins/GCodeReader/FlavorParser.py
index 2d0bd7b7c0..a49de266c4 100644
--- a/plugins/GCodeReader/FlavorParser.py
+++ b/plugins/GCodeReader/FlavorParser.py
@@ -320,7 +320,7 @@ class FlavorParser:
         if not global_stack:
             return None
 
-        self._filament_diameter = global_stack.extruders[str(self._extruder_number)].getProperty("material_diameter", "value")
+        self._filament_diameter = global_stack.extruderList[self._extruder_number].getProperty("material_diameter", "value")
 
         scene_node = CuraSceneNode()