All GZIW subwoofers have a new updated voice coil, and spirally stiffened IMPP dust cap with 3D structure logo. This significantly affects the resonance of the cone, so the redesigned GZIW guarantees an even tighter kick! Don´t get fooled by the affordable price! These budget class XSPL-monsters are designed with Klippel-optimization to squeeze out every single desibel that is possible to get. Voice coil cooling is very efficient and long excursion gives you a LOT of bass. Very linear impedance curve makes it possible to really extract all the power from the amp to these subwoofers.