An excellent pair of Audio Research mono amps! These are Class D amps, I believe and thus are efficient, cool running and very powerful and affordable, great sounding amps! Rated 450 watts each into 8 ohms, they will put out 650 watts each into 4 ohms! A fully balanced design, but they also have RCA inputs if needed. This pair work perfectly and are in excellent shape. Very conservatively rated an 8. Closer to a 9. One small ding on the one handle is all I could find. (see pics). Enough power to drive even large inefficient speakers with ease and will not warm up the room or make your power bill go up significantly! All original box, packing and manual. Can deliver if in the Seattle area! Paypal adds 3%. Check out my feedback and buy with confidence!