... 2.1 SD speakerSpeaker for cellphone, laptops, ipod, mp3 Enjoy music anytime Built-in amplifier with pure, ... with pure, vivid, distinct sound Compatible with laptops, iPod, MP3, MP4, MP5, cell phones, PSPs and more Power rating: ... 2 Impedance: 4 ohms Frequency: 90Hz to 20kHz S/N ratio: ≥80dB Power Supply: USB 5V/Rechargeable Li-ion ... optional PackingCarton Size:500*280*391mm 40sets/CTN N.W/G.W:14/14.6KGS