diff --git a/docs/limits.rst b/docs/limits.rst
index 265a567..7a48fe6 100644
--- a/docs/limits.rst
+++ b/docs/limits.rst
@@ -40,7 +40,7 @@ if you execute queries returning more than 1 MB of data.
 
 To increase these limits, set the ``-I`` and ``-m`` arguments when starting
 memcached. If you use Ubuntu and installed the package, you can modify
-`/etc/memcached.conf`, add ``-I 10`` on a newline to set the limit
+`/etc/memcached.conf`, add ``-I 10m`` on a newline to set the limit
 per cache key to 10 MB, and if you want increase the already existing ``-m 64``
 to something like ``-m 1000`` to set the maximum cache size to 1 GB.