Cambridge - Aero 3 Surrounds (Walnut) Drivers: 2 x 85mm (4") BMR drivers Mounting: Rear wall mount hardware Frequency response 80Hz - 22kHz Recommended amplifier power: 25-120 Watts Dimensions (W x H x D): 461 x 180 x 151mm (18.2 x 7.1 x 6.0") including grille