Visaton BF 45. Driver size: 45.7 mm (1.8 "). RMS rated power: 4 W, Peak Music Power Output (PMPO): 8 W, Frequency range: 90 – 20000 Hz. Driver cone material: Aluminium. Diameter: 45 mm, Weight: 32 g. Type: In-wall/On-wall/In-ceiling speakers, Dimensions (WxDxH): 61 x 61 x 26 mm, Audio output channels: 1.0