TC Sounds LMS Ultra 5400 18" DVC Subwoofer High-temperature low eddy-current stainless steel voice coil former Patent-pending LMS motor technology, 2+2 ohm 4&quot; diameter dual voice coil 11&quot; linear spider suspension with large integral lead-wires 525 oz. magnet motor structure with large anti-flux-modulation shorting ring Patent-pending XBR tall profile surround for 3&quot; peak-to-peak travel