diff --git a/websocket-sharp/Ext.cs b/websocket-sharp/Ext.cs
index d2f6b405..85074216 100644
--- a/websocket-sharp/Ext.cs
+++ b/websocket-sharp/Ext.cs
@@ -281,7 +281,7 @@ namespace WebSocketSharp
     internal static string CheckIfValidControlData (this byte[] data, string paramName)
     {
       return data.Length > 125
-             ? String.Format ("'{0}' is greater than the allowable max size.", paramName)
+             ? String.Format ("'{0}' has greater than the allowable max size.", paramName)
              : null;
     }