diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index 32f55c8..f365349 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -13,6 +13,7 @@
 from .ch03_cross import Ch03CrossCorrelationWindow
 from .ch03_psd import Ch03PsdWindow
 from .ch04_sampling import Ch04SamplingWindow
+from .ch04_window import Ch04WindowWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -23,6 +24,7 @@
         Ch03CrossCorrelationWindow,
         Ch03PsdWindow,
         Ch04SamplingWindow,
+        Ch04WindowWindow,
     ]