NHT AC1 - AudioCenter Channel Loudspeaker 2-way acoustic suspension, Two 5.25" long-throw polypropylene woofers 1" fluid-cooled aluminum dome tweeter, video shielded drivers Impedance: 8 ohms minimal, 6 ohms minimum, 75Hz - 21Hz, +/- 3dB, 87 db (2.83V at 1M) Amplifier: 30W/ch minimum, 150W/ch maximum, Crossover: 2.9kHz, 12dB/octave high-pass and low-pass Dimensions: 6.75"H x 19"W x 8"D, 17 lbs., High gloss black laminate