It is a modification that replaces the sloppy factory shifter rod with Heim type joints. You also drill a hole in the shifter linkage to shorten the throw and allow the shifter height to be adjusted. It was originally offered from DHS racing but the owner passed away. A friend of the owner now makes the kits available. Not sure if I can list the forum and supplier here because of forum rules. Here are the instructions to give you how the mod is done. If you are interested in doing it, PM me and will give you the information on the supplier.https://www.gl1800riders.com/attachm...ns-pdf.190913/