Polk Audio TL2 Speaker Center Channel (Each, Black) .75" Silk-dome tweeters 3.25" Composite Injection-molded cones with dynamic balance driver technology Power port Total frequency response: 90 Hz  24 kHz Time lens technology-the acoustic centers of the tweeter and mid-bass driver are located in the same plane for superior imaging Power port a patented Polk technology, extends the low frequency mid-bass driver response as it decreases air turbulence 3/4" Silk dome tweeters for crisp, clear imaging and smooth response that's never tiring 3 1/4" Composite Injection molded cones with dynamic balance driver technology Combination keyhole slot & 1/4" X 20 threaded insert fits all aftermarket ceiling and wall brackets for ultimate flexibility Eliminates "port noise" And bass output losses up to 3 dB Time Lens Technology-The acoustic centers of the tweeter and mid-bass driver are located in the same plane for superior imaging