diff --git a/SetManager.cs b/SetManager.cs
index 57f08fa..5a27e39 100644
--- a/SetManager.cs
+++ b/SetManager.cs
@@ -1,6 +1,5 @@
 // Copyright (C) 2017 Robert A. Wallis, All Rights Reserved.
 
-using System;
 using System.Collections.Generic;
 
 namespace ECSLight