diff --git a/extensions/webmail/main.py b/extensions/webmail/main.py
index be689f7f4..2aa9bf587 100644
--- a/extensions/webmail/main.py
+++ b/extensions/webmail/main.py
@@ -32,7 +32,7 @@ def init():
                               deflt="no",
                               help=_("Server needs authentication"))
     parameters.register_admin("MAX_ATTACHMENT_SIZE", type="int", deflt=2048,
-                              help=_("Maximum attachment size in KB"))
+                              help=_("Maximum attachment size in bytes (or KB, MB, GB if specified)"))
    
 
     parameters.register_user("MESSAGES_PER_PAGE", type="int", deflt=40,