... public security organs, procuratorial organs... E.TRADIO: Clear Speech Microphone,Omni Directional, Monitor Range 10-50sq.m,Size ... Bureau of Beijing ;Proceracy of Guangzhou;Classroom of Beijing University;Tongji Hospital etcParameter: Monitoring Range 10 ~ 50sq.mtransmiting ... 66g Detail Introduction: *Low noise, Low echo, clear speech, medium price.*blue/white coat microphone,widely voice-picking region ...