The SW118X-B is a single 18" subwoofer model designed to work in conjunction with an EJ2003-B or EL1503-B in applications where more bass is required. The SW118X is designed to work in systems using the SW118A powered subwoofer system. The onboard amplifier in the SW118A provides amplification for the passive driver in the SW118X. Each unit is finished in heavy duty black Duracoat™. The SM118X is also available in white Duracoat™ finish, model SW118X-W.