... trolley speaker, with USB/SD/FM radio/Remote control/wireless microphone Technical parametersFrequency response: 80Hz-18KHzRated power: 50RMSSpeaker Impedance ... , Model: KS-610 Scope of applicationGymnastics, dancing, teaching, product promotion, outdoor activities, travel, meetings, singing, refining piano ... groups, the elders'fitness outdoor. professional rechargeable wireless trolley speaker H610