The JBL ASB6128 Dual 18" Subwoofer is comprised of two 18" SVG Super Vented Gap low frequency drivers in a front-loaded, vented configuration. Perfect for fixed installation applications such as performing arts facilities, theatrical sound design, auditoriums, houses of worship, live clubs, dance-clubs/discotheques, sports facilities and themed entertainment venues, this subwoofer is high powered and Parallel/Discrete switchable.