B&W (Bowers & Wilkins) bookshelf-type speakers 686S2/MR (2units/Red Cherry) Configuration: 2-way bass reflex type system / drive unit: 1x 25mm aluminum Tita / 1x 130mm Woven Kevlar cone bass / midrange Reproduction frequency band: 50kHz at -6dB / playback frequency response from 54Hz: 62Hz - 22kHz  3dB reference axis / sound pressure level: 85dB (2.83V, 1m) / nominal impedance 8 (minimum 5.2) / crossover frequency: 4kHz Recommended amplifier output: 25W - 100W / 8 Dimensions: Height: 315mm  width: 160mm  depth: 229mm (cabinet, including grill and Terminal) / mass: 4.6kg (1 unit) Multi-language instruction manual URL (PDF):http://www.bowers-wilkins.jp/Downloads/Product/Manual/685-686-manual-600-Series.pdf