Micca MB42 Bookshelf Speakers, Passive, Needs Amplifier or Receiver, Not for Use Directly with Turntable, 4-Inch Carbon Fiber Woofer and Silk Dome Tweeter (Black, Pair) IMPORTANT: The MB42 is a passive speaker and needs to be used with an amplifier or receiver. It cannot be connected directly to a turntable! Balanced Woven carbon fiber woofer for enhanced transient and impactful bass. High performance Silk dome tweeter for smooth treble and accurate imaging. Ported enclosure delivers extended bass response with low distortion. Neutral and accurate sound signature with excellent vocal clarity. Compact classic design is easy to place and disappears into any room or decor. Sensitivity: 85dB 1W/1M, Frequency Response: 60Hz-20kHz (Typical In-Room), Dimensions Per Speaker: 9.5 (H) x 5.8 (W) x 6.5 (D), Impedance: 4-8 Ohms While the Micca speakers work just fine with most amplifiers and receivers rated for speakers designed to handle 6ohm or 8ohm speakers, the 4-8ohm rating is a reminder to users that these speakers do have impedance that go down to as low as 4ohms and care should be taken with the listening volume so as not to damage the amplifier or speakers.