diff --git a/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h b/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h
index 3a266bcc07..5cfa0cbbcd 100644
--- a/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h
+++ b/Source/Core/Core/HW/WiimoteEmu/ExtensionPort.h
@@ -22,6 +22,8 @@ enum ExtensionNumber : u8
   UDRAW_TABLET,
   DRAWSOME_TABLET,
   TATACON,
+
+  MAX
 };
 
 // FYI: An extension must be attached.
diff --git a/Source/Core/InputCommon/ControllerEmu/ControlGroup/Attachments.h b/Source/Core/InputCommon/ControllerEmu/ControlGroup/Attachments.h
index f92bd8b1fd..77d44df093 100644
--- a/Source/Core/InputCommon/ControllerEmu/ControlGroup/Attachments.h
+++ b/Source/Core/InputCommon/ControllerEmu/ControlGroup/Attachments.h
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "Common/CommonTypes.h"
+#include "Core/HW/WiimoteEmu/ExtensionPort.h"
 #include "InputCommon/ControllerEmu/ControlGroup/ControlGroup.h"
 #include "InputCommon/ControllerEmu/ControllerEmu.h"
 #include "InputCommon/ControllerEmu/Setting/NumericSetting.h"
@@ -34,7 +35,11 @@ public:
 
 private:
   SettingValue<int> m_selection_value;
-  NumericSetting<int> m_selection_setting = {&m_selection_value, {""}, 0, 0, 0};
+  // This is here and not added to the list of numeric_settings because it's serialized differently,
+  // by string (to be independent from the enum), and visualized differently in the UI.
+  // For the rest, it's treated similarly to other numeric_settings in the group.
+  NumericSetting<int> m_selection_setting = {
+      &m_selection_value, {""}, 0, 0, WiimoteEmu::ExtensionNumber::MAX - 1};
 
   std::vector<std::unique_ptr<EmulatedController>> m_attachments;
 };