diff --git a/docs/user/site.rst b/docs/user/site.rst
index 90b70bdd..c36d9543 100644
--- a/docs/user/site.rst
+++ b/docs/user/site.rst
@@ -159,7 +159,7 @@ roles : optional
       },
 
 simple_tc : package
-    Uplink traffic control
+    Uplink traffic control, ingress and egress values are specified in kiB/s.
     ::
 
       simple_tc = {