diff --git a/websocket-sharp/WebSocket.cs b/websocket-sharp/WebSocket.cs
index 6e307cb7..e7b0774f 100644
--- a/websocket-sharp/WebSocket.cs
+++ b/websocket-sharp/WebSocket.cs
@@ -3369,8 +3369,8 @@ namespace WebSocketSharp
     }
 
     /// <summary>
-    /// Sends the specified <paramref name="data"/> asynchronously using
-    /// the WebSocket connection.
+    /// Sends <paramref name="data"/> asynchronously using the WebSocket
+    /// connection.
     /// </summary>
     /// <remarks>
     /// This method does not wait for the send to be complete.
@@ -3379,9 +3379,17 @@ namespace WebSocketSharp
     /// A <see cref="string"/> that represents the text data to send.
     /// </param>
     /// <param name="completed">
-    /// An <c>Action&lt;bool&gt;</c> delegate that invokes the method called when
-    /// the send is complete. A <see cref="bool"/> passed to this delegate will be
-    /// <c>true</c> if the send has done with no error.
+    ///   <para>
+    ///   An <c>Action&lt;bool&gt;</c> delegate or <see langword="null"/>
+    ///   if not needed.
+    ///   </para>
+    ///   <para>
+    ///   The delegate invokes the method called when the send is complete.
+    ///   </para>
+    ///   <para>
+    ///   <c>true</c> is passed to the method if the send has done with
+    ///   no error; otherwise, <c>false</c>.
+    ///   </para>
     /// </param>
     /// <exception cref="InvalidOperationException">
     /// The current state of the connection is not Open.