Premium 5.1-Channel Home Theater Speaker System (PID 10565). Each speaker features a 3" polypropylene mid-range driver and a 3/4" aluminum dome tweeter. They can support up 100 watts of power and have an impedance of 8 ohms The speakers handle frequencies from 110Hz to 20KHz 3dB, with the crossover between the mid-range and tweeter drivers set to 3.5KHz. They measure only about 6.9" x 4.3" x 4.3" (HWD) and weigh about 2.9 lbs. each, making them easy to mount almost anywhere. They are equipped with a universal 1/4" threaded insert mounting option and have rear-firing ports, so they sound best when there is some breathing room behind them .