diff --git a/geomagio/Controller.py b/geomagio/Controller.py
index b1d4302fa45ebf277891a528af30e672e7c3a1cc..adf42c832281298b5f26efb82c4013453d740cc3 100644
--- a/geomagio/Controller.py
+++ b/geomagio/Controller.py
@@ -707,7 +707,7 @@ def parse_args(args):
         const=True,
         help="""
                 Run the last N seconds.
-                Default 172800 (last) when interval is day,
+                Default 172800 (last 2 days) when interval is day,
                 Default 7200 (last 2 hours) when interval is hour,
                 Default 3600 (last hour) when interval is minute,
                 Default 600 (last 10 minutes) otherwise.