Loudspeaker, System can play MP3 and WAM format in the udisk. A great help at home, office, factory, hospital, school, nursing home, church, retreat, camp, meeting, restaurant, party, ballgame, any place or event - one to one conversation or group activity - and in a car, bus, plane or train to get above engine and road noisesPerformance indexThe machine is used in the design of dynamic ...