This ducting is original equipment on the 997 GT3, and works perfectly for fast street and track brake cooling purposes with OEM fitment and performance. Shaped in a wind tunnel and designed by Porsche engineers, this duct is guaranteed to work for your fitment with no additional hardware. Clips directly to the lower suspension control arm with integrated clips. While this duct is not much larger than the standard 997 Carrera duct, it has been channelled more agressively to divert air more effectively.