Check out this thread, only so I don't have to re-type
http://www.pressurewashinginstitute.com/board/upload/showthread.php?s=&postid=18279&t=8978#post18279
http://www.pressurewashinginstitute.com/board/upload/showthread.php?s=&postid=18279&t=8978#post18279