diff --git a/common/board/relay_x4.yaml b/common/board/relay_x4.yaml
index ac5e689..dbf420d 100644
--- a/common/board/relay_x4.yaml
+++ b/common/board/relay_x4.yaml
@@ -1,2 +1,4 @@
+# https://devices.esphome.io/devices/esp-12f-relay-x4/
+
 esp8266:
   board: esp01_1m
\ No newline at end of file