T-Slot Mounting Kit replaces the standard mounting hardware included in the DownLoader, J-Pro, J-Pro 2 and J-Loader. The MPG6604 utilizes the T-slot in all Malone aero bars and most aftermarket aluminum load bars with T-slots. Provides a seamless look to the carrier installation and allows more under bar clearance. Longer bolts may be required for Pre-2020 Malone J-Racks.