12? Single 4 Ohm Cobalt Series Subwoofer Power Handling: Peak: 500 watts RMS: 200 watts Impedance: Single 4 Ohm UV-treated paper cone woofer Nitrile-butadiene rubber surround Polypropylene dust cap Custom stamped steel frame Interlaced Conex spider Stitched and looped tinsel leads Rugged spring terminals up to 10-gauge 3-stage vented back plate 1.5? high temperature copper voice coil with Kapton former Frequency response: 25-250 Hz Sensitivity: 87.2 dB