The Edge Products 98654 EAS Shift-On-The-Fly Accessory gives you the ability to easily change custom tunes from the Insight CS2 or CTS2 monitor in your 2004.5-2010 GM Silverado/Sierra 6.6L Duramax. Forget having to drill a hole in your dash for a manual switch. Tunes can be conveniently changed right from the screen of your Insight. Many tuning companies utilize a voltage signal to prompt a custom tune level change. Edge has designed this product to produce voltage signals between 1v, 2v, 3v, 4v, and 5v, right from your Insight, allowing for tune changes without the need for a separate switch.