Evolution® ZR 6.50 in. / 165 mm 2-Way Component Systems: 6.50 in. / 165 mm Woofers; 1.0 in. / 25 mm Aluminum Dome Tweeters This new range of reference component systems fully demonstrates JL Audio's obsession with accurate sound reproduction. Woofers: Custom-engineered, proprietary cast aluminum woofer baskets were designed to provide maximum rear open area while also incorporating JL Audio's patented "Elevated Frame" cooling system. This cooling technology, shared with JL Audio's W7 subwoofers, allows air to flow directly across the top-plate and onto the voice coil windings to greatly improve linearity at all listening levels. Tweeters: 1.0 in. / 25 mm aluminum dome tweeter Crossover Networks: All of these quality components are enclosed in a newly designed, polycarbonate case with a classy metal "ZR" logo that will look at home in any high-end installation. Continuous Power Handling: 85 Watts Peak Music Power: 255 Watts Rec. Power Range (per channel): 25 - 175 Watts System Efficiency: 89.5 dB @ 1W/1m System Nominal Impedance: 4 ohms System Frequency Response: 48 Hz - 25 KHz ± 3 dB