diff --git a/ctapipe/image/extractor.py b/ctapipe/image/extractor.py
index 4ccae191f10..f7563de5c79 100644
--- a/ctapipe/image/extractor.py
+++ b/ctapipe/image/extractor.py
@@ -5,7 +5,7 @@
 __all__ = [
     'ImageExtractor',
     'FullWaveformSum',
-    'UserWindowSum',
+    'FixedWindowSum',
     'GlobalPeakWindowSum',
     'LocalPeakWindowSum',
     'NeighborPeakWindowSum',
@@ -254,9 +254,9 @@ def __call__(self, waveforms):
         return charge, pulse_time
 
 
-class UserWindowSum(ImageExtractor):
+class FixedWindowSum(ImageExtractor):
     """
-    Extractor that sums within a window defined by the user.
+    Extractor that sums within a fixed window defined by the user.
     """
     window_start = Int(
         0, help='Define the start position for the integration window'
diff --git a/ctapipe/image/tests/test_extractor.py b/ctapipe/image/tests/test_extractor.py
index 702be94c0a8..5a30575ddee 100644
--- a/ctapipe/image/tests/test_extractor.py
+++ b/ctapipe/image/tests/test_extractor.py
@@ -10,7 +10,7 @@
     subtract_baseline,
     ImageExtractor,
     FullWaveformSum,
-    UserWindowSum,
+    FixedWindowSum,
     GlobalPeakWindowSum,
     LocalPeakWindowSum,
     NeighborPeakWindowSum,
@@ -103,9 +103,9 @@ def test_full_waveform_sum(camera_waveforms):
     assert_allclose(pulse_time[1][0], 62.359948, rtol=1e-3)
 
 
-def test_user_window_sum(camera_waveforms):
+def test_fixed_window_sum(camera_waveforms):
     waveforms, _ = camera_waveforms
-    extractor = UserWindowSum(window_start=45)
+    extractor = FixedWindowSum(window_start=45)
     charge, pulse_time = extractor(waveforms)
 
     assert_allclose(charge[0][0], 232.559, rtol=1e-3)