... .support MP3,CD,PC 4.certificate:ISO 9001:2000 2.1 Multimedia SpeakerFeatures1.speaker sensitivity high2.grinds sand material3.MP3,CD ... unit and high sensitivity, outstanding sound quality and complete protection.2. No installation, with speaker bracket.3. Application:classroom, ... CE and ISO 9001:2000 certified.8.Application:school,classroom,multimedia room, multifunction room and classroom and so on. ...