... range:GSM,GSM,DCS,PHS and 3G signal ET101B Portable mobile phone detector1. TechnologyDetects wideband:a. can detects th RX frequency ... (Blue)& RF detecting light(Red).*When it find the mobile phone signal, the red light will be on, much nearer ... etc3, Prison, jail4, Gas station, oil station, oil field etc5, Every place which not allowed to use the mobile phone EST101B Portable mobile phone detector