Cellular Jammer - B-2000 Signal Blocker serves to eliminate the signal handpone, very useful used in the meeting / conference, library, school, performance space, and others. Works on 800MHz CDMA lines, GSM 900MHz, GSM 1800MHz, 1900MHz CDMA, and 3G with coverage from 1000 to 2000 m2 which can diadjust at the time of installation.