diff --git a/addon/appModules/splstudio/__init__.py b/addon/appModules/splstudio/__init__.py
index 270cf17d0..4cb71bf14 100644
--- a/addon/appModules/splstudio/__init__.py
+++ b/addon/appModules/splstudio/__init__.py
@@ -68,7 +68,7 @@ def new(*args, **kwargs):
 SPLMinVersion = "5.30"
 
 # Threads pool.
-micAlarmT = None
+micAlarmT: Optional[threading.Timer] = None
 micAlarmT2 = None
 libScanT = None