The JBL SRX728S Dual 18" Subwoofer is built to deliver smooth, clean, accurate low-end. With a pair of 18" Differential Drive woofers, it handles an amazing 1600W power (continuous). Large, open ducts minimize port turbulence and the heavily braced JBL enclosure assures tight, solid bass response. Designed to present a minimum frontal area, the subwoofer enclosure offers complete input connection flexibility with 2 Neutrik Speakon jacks. A recessed, external switch allows selection of either contacts +1/-1 or +2/-2 while an internal connector allows you to drive each woofer from a separate amplifier channel. The speaker cab is constructed of top-quality birch plywood and coated in rugged DuraFlex. Each woofer is housed in an isolated chamber and the enclosure is heavily braced to maximize low-frequency performance. The attractive CNC machined, 16-gauge steel grille is internally lined with acoustically transparent foam to provide the JBL SRX728S with additional driver protection and a very professional appearance. This subwoofer excels when paired with the PA speakers (sold separately).