diff --git a/README.md b/README.md
index 3d44441..f5df067 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 Package **iid** provides quazi‐ monotonically‐increasing unique‐identifiers.
 
+The serialized form of the **IID** is safe to use as a _file_ or _directory_ name.
+
 
 ## Documention