diff --git a/websocket-sharp/Net/WebSockets/HttpListenerWebSocketContext.cs b/websocket-sharp/Net/WebSockets/HttpListenerWebSocketContext.cs
index 2f37e110..31f015e7 100644
--- a/websocket-sharp/Net/WebSockets/HttpListenerWebSocketContext.cs
+++ b/websocket-sharp/Net/WebSockets/HttpListenerWebSocketContext.cs
@@ -231,16 +231,21 @@ namespace WebSocketSharp.Net.WebSockets
     }
 
     /// <summary>
-    /// Gets the value of the Sec-WebSocket-Key header included in the handshake
-    /// request.
+    /// Gets the value of the Sec-WebSocket-Key header included in
+    /// the handshake request.
     /// </summary>
-    /// <remarks>
-    /// This property provides a part of the information used by the server to
-    /// prove that it received a valid WebSocket handshake request.
-    /// </remarks>
     /// <value>
-    /// A <see cref="string"/> that represents the value of the
-    /// Sec-WebSocket-Key header.
+    ///   <para>
+    ///   A <see cref="string"/> that represents the value of
+    ///   the Sec-WebSocket-Key header.
+    ///   </para>
+    ///   <para>
+    ///   The value is used to prove that the server received
+    ///   a valid WebSocket handshake request.
+    ///   </para>
+    ///   <para>
+    ///   <see langword="null"/> if the header is not present.
+    ///   </para>
     /// </value>
     public override string SecWebSocketKey {
       get {