When technology advances, products do as well. Does Lamborghini need to refine their cars every 2 years? NO, they do because they can. After 6 years, it is time for a change. Say "See Ya!" to the old MOFO, and welcome the MOFO-X subwoofers! The motor is refined and increases efficiency dramatically! MOFO-X subs use a non-pressed pulp cone for durability and smooth low bass. Like the original MOFOs, this model still use an aluminum dustcap that couples to the voice coil former and extends over the cone. Why? The fins brace the cone and eliminate cone flex during high excursion. Since the cap is aluminum and coupled to the coil former, it acts as a heat sink or heat extractor. The MOFO-X subs yield superior performance!