Single center speaker designed to accommodate the rear surround channel in Polk"s RM6750 speaker system * Dual 3.25-inch polymer composite cone midrange drivers and 0.75-inch high-performance silk dome tweeter * PowerPort bass vent technology improves the lower midrange response for better sat/sub blending * Integrated baffle and grille design disperses the sound beautifully for clear, well-balanced, room-wise audio * Magnetically shielded against video interference