TEAC MP-2XS. Mid-range driver size: 30 mm, Magnet type: neodymium. RMS rated power: 2.4 W, Peak Music Power Output (PMPO): 4 W, Frequency range: 100 - 12500 Hz. Speaker interface type: USB, Headphone connectivity: 3.5 mm. Weight: 0.15 kg. Battery type: AA