Visaton FRS 7-4 Ohms, 2.5"" Full-Range Loudspeaker, Power rating: 8 W RMS, Impedance: 4 Ohm, 88 db / w / m, Frequency range: 200 - 20,000 (-10 dB), High quality, moisture impregnated metal housing, Suitable for column speakers and bass reflex cabinets