1 files changed, 4 insertions, 0 deletions

diff --git a/README.md b/README.md
index 629b252..a8b93ca 100644
--- a/README.md
+++ b/README.md
@@ -301,6 +301,10 @@ Unacceptable input example:
 httds://notquiteright.org
 ```
 
+#### `Stdlib::MAC`
+
+Matches MAC addresses defined in [RFC5342](https://tools.ietf.org/html/rfc5342).
+
 #### `Stdlib::Unixpath`
 
 Matches paths on Unix operating systems.