RE Audio REX5 5.25-Inch Co-Ax Kit - Set of 2 Power Handling: 100W, Nominal Rating: 50W Frequency Response: 75-20,000Hz, Efficiency: 89dB Impedance: 4 Ohm, Lowest Resonant Frequency: 100Hz, Crossover Frequency: 4,500Hz Mounting Depth: 55mm, Dimensions: 160mm x 160mm Surround: Rubber, Black Polyester Diaphragm: P.E.I.