polk audio csi a4 black center channel loudspeaker csia4bk
polk audio csi a4 black center channel loudspeaker csia4bk 1 ' silk/polymer dome tweeter dual 5-1/4 ' mid/woofers magnetic shielding all-mdf construction acoustically inert stamped driver baskets floating anti-diffraction grilles dual bi-ampable gold-plated 5-way binding post inputs black finish sold as a single