On my instruction sheet is says EC/CC. I originally figured that meant Extended Cab and Crew Cab. Works for both. I guess I'll find out next month when the dealer installs it at day 1 (unless someone here installs it on a SCAB first). The product looks awesome and sounds just as good. It seems like many exhausts need modification to one thing or another. Whether it's a bracket that doesn't line up or bolts that don't fit or whatever. Why can't they all just smoothly fit right on? I have no idea.