diff --git a/docs/configuration.md b/docs/configuration.md
index 2ff0f324b..f9b89febc 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -753,7 +753,7 @@ interpretation of the options.
       no
     </td>
     <td>
-      Specify a `duration` by providing an integer and a unit. Valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`. For example, `3m` is a valid duration. If you do not specify a `duration` or specify an integer without a time unit, this defaults to 20 minutes.
+      Specify a `duration` by providing an integer and a unit. Valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`. For example, `3000s` is a valid duration; there should be no space between the integer and unit. If you do not specify a `duration` or specify an integer without a time unit, this defaults to 20 minutes.
     </td>
   </tr>
 </table>