The Rockville APM8 Active Studio Monitor Comes in Pairs and each monitor is bi-amped. Each speaker has 250 watts peak output power and 125 watts RMS giving you a total of 500 watts peak and 250 watts RMS per pair. To get the most efficiency we use a class D amplifier. We use an eight-inch woofer. This will out-perform a regular five-inch woofer any day! The bass sounds amazing on these! The woofer has an injection molded polypropylene cone. We developed the speakers with the most optimized magnet structure cone and cabinet space with the goal of reproducing the sound to play back exactly the way it was recorded! The rear-firing port is shaped and designed by sound engineers to reduce port turbulence and deliver distortion-free top sound quality! These Monitors have all your standard studio inputs and outputs such as a 1/4-inch and XLR combo input jack RCA input 3.5mm headphone output. We also added a USB port.