The rear bracing on the NC Sport and Hard Bar bars doesn't extend all the way to the top of the main hoop, and some track organizations require this. For maximum protection, this Petty bar runs from the center of the main hoop down to the passenger floorboard. The bar is removable for day-to-day use but can be bolted in for track use. A bracket will remain in the footwell, and a small cut in the carpet will let it protrude. It's fairly subtle, most people don't notice it in our car.
While a passenger can actually sit in the seat with the bar installed, we do not recommend driving with this setup. A track instructor will definitely refuse to ride with you.
Must be purchased at the same time as the roll bar.