Coaxial Speaker System: 5.25-inch (130 mm) Woofer, 0.75-inch (19 mm) Aluminum Dome Tweeter C1 speakers deliver real substance and great audio performance in a format designed for easy fit behind factory grilles. C1 woofer drivers benefit from proprietary FEA modeling and JL Audio's expertise in low-frequency driver design. This knowledge is used to create speakers that can play loudly, while maintaining a smooth, dynamic, low distortion sound. At the core of the C1-525x is a proprietary, stamped, steel 5.25-inch (130 mm) frame and a DMA-optimized motor system. A mineral-filled, injection-molded polypropylene cone is suspended with a rubber surround on the front, and a carefully engineered flat Conex® spider at the top of the voice coil, to precisely control motion and prevent impact between the voice coil and the back plate. Tinsel leads are carefully routed and attached to the spider to prevent fatigue and buzzing. These are the same kinds of features and materials normally found on much more expensive loudspeakers. Equipped with a true, edge-driven, aluminum dome tweeter, C1 speakers stand further apart from others in its category with superior high-frequency clarity and definition. The tweeter’s design has inherently excellent off-axis response and high-frequency extension. It also benefits from the damping of a silk surround suspension and Ferrofluid in the voice coil gap, along with the superior strength of a neodymium magnet circuit. A true, 2nd order high-pass filter is employed to further enhance smoothness and improve power handling. When it comes to value, C1 is the real deal! Sold as a pair. Grilles not available.