diff --git a/notecard/hub.py b/notecard/hub.py
index c915f89..b75f8ab 100644
--- a/notecard/hub.py
+++ b/notecard/hub.py
@@ -60,7 +60,7 @@ def set(card, align=None, details=None, duration=None, host=None, inbound=None,
         duration (int): When in `continuous` mode, the amount of time, in minutes, of each session (the minimum allowed value is `15`). When this time elapses, the Notecard gracefully ends the current session and starts a new one in order to sync session-specific data to Notehub.
         host (str): The URL of the Notehub service. Use `"-"` to reset to the default value.
         inbound (int): The max wait time, in minutes, to sync inbound data from Notehub. Explicit syncs (e.g. using `hub.sync`) do not affect this cadence. When in `periodic` or `continuous` mode this argument is required, otherwise the Notecard will function as if it is in `minimum` mode as it pertains to syncing behavior. Use `-1` to reset the value back to its default of `0`. A value of `0` means that the Notecard will never sync inbound data unless explicitly told to do so (e.g. using `hub.sync`).
-        mode (str): The Notecard's synchronization mode.
+        mode (str): The Notecard's synchronization mode. NOTE: The Notecard must be in `periodic` or `continuous` mode to use the onboard GPS module.
         off (bool): Set to `true` to manually instruct the Notecard to resume periodic mode after a web transaction has completed.
         on (bool): If in `periodic` mode, used to temporarily switch the Notecard to `continuous` mode to perform a web transaction.\n\nIgnored if the Notecard is already in `continuous` mode or if the Notecard is NOT performing a web transaction.
         outbound (int): The max wait time, in minutes, to sync outbound data from the Notecard. Explicit syncs (e.g. using `hub.sync`) do not affect this cadence. When in `periodic` or `continuous` mode this argument is required, otherwise the Notecard will function as if it is in `minimum` mode as it pertains to syncing behavior. Use `-1` to reset the value back to its default of `0`. A value of `0` means that the Notecard will never sync outbound data unless explicitly told to do so (e.g. using `hub.sync`).