Uni-Q Two-way 160mm Round Ci160.2CR in-ceiling speaker features KEF’s patented Uni-Q driver array that allows sound to disperse more evenly throughout the room. The extremely shallow mounting depth allows you to install the Ci160.2CR where other speakers in its class won’t fit. Model Ci160.2CR Nominal Impedance 8Ω Ohm Sensitivity (2.83V/lm) 89dB Frequency Response 52Hz-20kHz (+/-6dB) open-backed Crossover Frequency 2.5kHz Drive Units LF: 160mm (6.5in.)HF: 16mm (0.6in.) Recommended Amplifier 10-100W External Dimensions Diameter: 234.6mm (9.24in.)Depth: 88.7mm (3.49in.) Cut-Out Dimensions Diameter: 196mm (7.71in.) Mounting Depth from Surface 84.5mm (3.33in.) Weight 1.4kg (3.1lbs) Optional Rough in Frame RIF160R Optional Rear Enclosure RNC160R