diff --git a/doc/adapter-api.txt b/doc/adapter-api.txt
index 48466ab..9b2721c 100644
--- a/doc/adapter-api.txt
+++ b/doc/adapter-api.txt
@@ -269,6 +269,21 @@ Properties	string Address [readonly]
 			restart or unplugging of the adapter it will reset
 			back to false.
 
+		string PowerState [readonly, experimental]
+
+			The power state of an adapter.
+
+			The power state will show whether the adapter is
+			turning off, or turning on, as well as being on
+			or off.
+
+			Possible values:
+				"on" - powered on
+				"off" - powered off
+				"off-enabling" - transitioning from "off" to "on"
+				"on-disabling" - transitioning from "on" to "off"
+				"off-blocked" - blocked by rfkill
+
 		boolean Discoverable [readwrite]
 
 			Switch an adapter to discoverable or non-discoverable