2.0 Wireless+3 IN 1 USB Speaker 1.for CD/PC/MP3 2.3 in 1:receiver,amplifier,speaker 3.manufacturer OEM&ODM ... automatically search for signals, no interference, no string frequency.5.all range frequency.6.Material: Baking varnish grille net.7 ... and acoustic feedback.9.External USB interface to upgrade.10.Easy installation and commissioning. Large power supply.11.Application: multimedia room,technique ...