diff --git a/gpiozero/input_devices.py b/gpiozero/input_devices.py
index 51c087c..8fa1a6b 100644
--- a/gpiozero/input_devices.py
+++ b/gpiozero/input_devices.py
@@ -251,7 +251,7 @@ class Button(HoldMixin, DigitalInputDevice):
 
     :param float bounce_time:
         If ``None`` (the default), no software bounce compensation will be
-        performed. Otherwise, this is the length in time (in seconds) that the
+        performed. Otherwise, this is the length of time (in seconds) that the
         component will ignore changes in state after an initial change.
 
     :param float hold_time: