Features. RMS: 6W PMPO: 500W SPEAKER UNIT: 2 x 3W (FULL RANGE) SENSITIVITY: 65dB MPEDENCE: 4 Ohm FREQUENCY RANGE: 150Hz-20kHz DEFAULT POWER: USB 5V OPTIONAL: AAA SIZE BATTERY AVAILABLE ( NO NEED A / C POWER) We have our own brand which is being sold in Asia, America and Europe now. And if you want, we can do OEM, too. We hope to establish good business relationship with you. We look forward to a right buyer. I welcome you with my whole heart. Moreover you will be relieve with that Korea is the strongest country in IT in the world. Plz let me know your email address so that we can send you information of our products. I look forward to your prompt reply.