All components of this MONOLITH subwoofer have been carefully selected and precisely coordinated. Due to its hardness and high rigidity combined with its low weight, the Aluminum membrane is ideally suited for detailed and extremely low-distortion reproduction quality in the intended area of application. ∅ 25 cm Subwoofer Frequency Response: 25 Hz – 100 Hz* Nominal Power Handling: 200 W RMS* Nominal Impedance: 4 ohms Voice Coil Diameter: 2" / 51 mm Voice Coil Winding Height: 25.2 mm Mounting Cutout Diameter: 238 mm Mounting Depth: 138 mm