Club woofers offer better efficiency and more power. JBL uses progressive spiders to ensure the best possible control at the excursion limits, as opposed to the far more common linear spiders. The benefit is a much more controlled low frequency excursion with a much tighter bass response. With their high-roll surrounds, patented cone design and long excursion, Club woofers deliver deep, powerful bass with greater precision than conventional woofers. And with the exclusive SSI (Smart Selectable Impedance) switch, you can choose between 2 or 4 Ω impedance for maximum configuration flexibility. It has everything you expect from a woofer. SSI (Selectable Smart Impedance) Most car audio systems are designed for an impedance of 2 or 4 Ω. Club subwoofers feature an exclusive dual impedance switch that allows you to select one of two load impedance options. SSI allows you to reconfigure your system with the simple flip of a switch, something not offered by any other supplier. High-Roll Surround The Club woofers are equipped with a high-roll surround, which provides excellent suspension of the cone edges while maximising excursion. It not only increases the cone area, but also offers remarkable linear stability and reliability. Proprietary cone design JBL subwoofer cones aren't just built to thunder, they're built to last. Club woofers feature an exclusive cone design that provides superior rigidity for long-lasting performance.