Q Acoustics Concept 20 Bookshelf Speakers (Pair) (Gloss Black) With its revolutionary GelcoreTM construction cabinet, the What Hi-Fi? award-winning Concept 20 speaker allows music lovers to enjoy genuine high-end sonic performance at an affordable price Enclosure: 2-way reflex. Bass Unit: 125mm. Treble Unit: 25mm Frequency Response (+/-3dB): 64Hz-22kHz. Nominal Impedance: 6 ohm. Minimum Impedance: 4 ohm Sensitivity: 88dB. Recommended Power: 25-75w. Crossover Frequency: 2.9kHz Box includes: (2) Concept 20 Bookshelf Speakers, (2) Speaker Grills, (2) Port Bungs, (1) User Manual GelcoreTM Construction -  Means music lovers can enjoy genuine high end  sonic performance and with the option of either lacquered gloss black,  or lacquered gloss white; not only will the speakers sound amazing, they  will also look beautiful. Enclosure type: 2-way reflex, Bass Unit: 125mm, Treble Unit: 25mm Frequency Response (+/- 3 dB): 64Hz - 22kHz, Nominal Impedance: 6ohm, Minimum Impedance: 4ohm Sensitivity: 88dB, Recommended Power: 25 - 75w, Crossover Frequency: 2.9kHz Includes: (2) Concept 20 Bookshelf Speakers, (2) Speaker Grills, (2) Port Bungs, (1) User Manual