MTX TN10-04 10-Inch Single 4-OHM Subwoofer 150-Watt RMS ALDS Asymmetrical Linear Drive System with a flat progressive spider and extended pole piece for smooth, linear, piston like drive Exclusive Spider Plateau Venting cooling system cools at the voice coil Rubber surround for greater durability and longetivity of the sub 28 oz. Magnet structure MTX Audio logo on dust cap