Polk Audio TL 1 Satellite Speaker (Each, Black) Time Lens Technology-The acoustic centers of the tweeter and mid-bass driver are located in the same plane for superior imaging TL1 Satellite Aperiodic-Tuned Rear Port enables better blending with a subwoofer 2 1/2" Long-Throw Drivers With Dynamic Balance Driver Technology 1/2" Silk Dome Tweeters for crisp, clear imaging and smooth response that's never tiring. Combination Keyhole Slot & 1/4" x 20 Threaded Insert fits all aftermarket ceiling and wall brackets for ultimate flexibility Time Lens Technology-The acoustic centers of the tweeter and mid-bass driver are located in the same plane for superior imaging 2 1/2" Long-Throw Drivers With Dynamic Balance Driver Technology 1/2" Silk Dome Tweeters for crisp, clear imaging and smooth response that's never tiring. Combination Keyhole Slot & 1/4" x 20 Threaded Insert fits all aftermarket ceiling and wall brackets for ultimate flexibility