Dual 15-inch woofers with a 2″inch diameter edge-wound ribbon voice coil for solid and extended bass, high efficiency and power handling JBL 2412 1-inch ferro-fluid cooled compression driver with titanium diaphragm delivers clean and warm high notes and uncompromised reliability JBL SonicGuard technology constantly protects the high frequency driver from excessive power Precision-crafted crossover feeds drivers with clear-cut frequencies and delivers coherent summation in the crossover region Progressive Transition waveguide provides superior coverage control, reduced distortion and smoother frequency response Rugged enclosure made from 15mm MDF (Medium Density Fiberboard) Dent-resistant grille protects the internal from damage on the move or during the show.