DESC: The P5 has some unique design features that make it a force to be reckoned with. The cone is made of polypropylene, which is a strong, lightweight and durable cone material. The P5 Turbo Cone design contains spiral ribs for increased rigidity, which also act to virtually eliminate all standing waves on the cone´s surface. Even lower distortion is realized as a result. The surface area has also been increased, improving Sound Pressure Level by increasing the amount of air moved with each thump of the cone.