GoldMaster S-9. System type: 2.0 system, Recommended usage: universal, Speaker placement: Portable, Tabletop/bookshelf. RMS rated power: 5 W, Frequency range: 90 - 20000 Hz, Impedance: 4 Ом. Connectivity technology: Wired, Speaker interface type: USB. DC input voltage: 5 V. Power source type: AC