Microlab SP-MD220WH 6 Watt 2.0 Portable Stereo Speaker (White) Subwoofer RMS Power: Amplifier: 2 Watt RMS Speaker: 2 Watt x 2 Driver: Speakers: 1.5 x 2 Frequency Response: 150Hz - 20KHz Signal to Noise Ratio(SNR): > 75 dB Impedance: Speakers: 4 ohms Power Supply: USB 5 V, or 3.7 V lithium rechargeable battery Dimension: 7.68(L) x 2.34(H) x 2.24(D) Weight: 0.77 lbs.(0.35 kg)