Which model? Lansing sells several. I am going to guess it is one in their WindJammer series.
If you are in Chicago, you would be well advised to talk with Window4U. He serves the Chicago area and is one of the best pros that I know of.
You can click on his name in this thread and get connected with him.http://www.vinyl-replacement-windows.com/forum/viewtopic.php?f=1&t=4979