B-52 MX-18S 18" 550W Subwoofer Extend the low-frequency response of any MX series full-range system to its lowest octave with the B-52 MX-18S 18" 550W Subwoofer. The MX-18S uses an American-made cast-frame 18" subwoofer with a 3.5" high-temperature polyamide voice coil. The rugged speaker cabinet features metal bar handles, 16-gauge perforated steel grille, rubber feet, and protective metal corners. Finished with impact-resistant black carpet. Input connectors include 2 - 1/4" metal phone jacks and a genuine Neutrik NL4 connector. The B-52 subwoofer speaker has a polemount adapter that makes it easy to install a metal tube to support the MX-15.