diff --git a/saqc/funcs/rolling.py b/saqc/funcs/rolling.py
index bcc0d2e52ecca3e4ec851beb66ff7a6d9746792f..7cc212c5cb633110f1733e8ddfc55089be2c1523 100644
--- a/saqc/funcs/rolling.py
+++ b/saqc/funcs/rolling.py
@@ -186,7 +186,7 @@ def _hroll(
         if freq is None:
             raise ValueError(
                 f"Rolling over more than one column is only supported if either the data has a unitary"
-                f'sampling rate, or window is an Integer. "{window}" was passed and combined {field} '
+                f'sampling rate, or window is an integer. "{window}" was passed and combined {field} '
                 f"index is not unitarily sampled"
             )
         else: