The JackHammers are loaded with features that make them rock. The JH45 subwoofers have a silver stamped basked, rubber magnet cover, and industrial-looking riveted dust cap design. The JH55 subwoofer has a black stamped basket design for structural strength, a stamped back panel with MTXs aggressive looking Gothic logo, and a large rubber boot create a powerful looking package. MTX Jack Hammer JH551204 12" JackHammer 55 Round Series Subwoofer Power Handling: Peak: 800 watts RMS: 400 watts Impedance: Single 4 Ohms Polypropylene woofer cone Rubber surround Stitched Cone for added durability and style Precision Stamped Basket for greater structural integrity FEA optimized roll geometry to maximize excursion without sacrificing cone surface area ALDS Asymmetrical Linear Drive System with a flat progressive spider and extended pole piece for smooth, linear, piston like drive Industry leading thermal power handling using 428° F High Temperature Voice Coil Wire Series: JackHammer Type: Subwoofers Cone Material: Vac PP Surround Material: Rubber Voice Coil: Single Voice Coil Construction: 1-3/4" Single voice coil using 428° F High Temperature Voice Coil Wire Damper (Spider): Industry leading Spider Plateau Venting cooling system cools at the voice coil Magnet Construction: 70oz. Magnet structure