diff --git a/docs/runtime_options.md b/docs/runtime_options.md
index 5e9a073a..da21afc7 100644
--- a/docs/runtime_options.md
+++ b/docs/runtime_options.md
@@ -7,7 +7,7 @@ This document describes a set of runtime flags available in cAdvisor.
 cAdvisor stores the latest historical data in memory. How long of a history it stores can be configured with the `--storage_duration` flag.
 
 ```
---storage_duration: How long to store data.
+--storage_duration=2m0s: How long to store data.
 ```
 
 ## Housekeeping