Specifications Input Sensitivity: 640mV Drive Units: 52mm x2(4 ohms) Output Power: 2.5w Frequency Range: 150Hz-18KHz. S/N Ratio: -69dB. Connector: 3.5mmST Power Supply: DC 6.0V(AAAx4 Batteries) or AC adaptor(output DC6V/800mA) Material: ABS Plastic Audio source: Ipod; Ipod mini; MP3; MD,CD, Notebook open Dimension: 207(w)*53(d)*62(h)mm Foldable Dimension: 112(w)*62(d)*62(h)mm