The second of five JVC CS-HX car speakers, the JVC CS-HX637X is an upgrade from the JVC CS-HX537X in that each speaker offers a larger 6-1/2” (versus 5-1/4”) Carbon Fiber Composite Olefin woofer, not to mention a superior power output of 250w (versus 230w), an improved sensitivity of 86dB (versus 85dB), and a lower frequency range of 30 – 25,000Hz (versus 40 – 32,000Hz). In addition, the CS-HX637X comes equipped with a 1-31/32” Pulp Cone midrange and a ½” Poly-Ether Imide Dome tweeter. The CS-HX637X also boasts an impedance of 4 ohms, heat-resistant voice coils, a stylish silver trim plate, and a black grille. The JVC CS-HX537X retails for a slightly more expensive $79.95 (versus $69.95) and comes with a 1 year limited warranty.