The world's infinite distance voice transmission ( using the GSM signal transmission, no distance limit can be inter-provincial cross-border) dual microphone design, ultra-clear sound Small size as a match box ,
portable 900/1800/1900 frequency
With lithium battery inside too
Function of SMS to control voice activated on or off. If you don't want to voice activated function in some times , you can remote control to disactivate it . It can save power .
Voice activated function. If the surrounding voice is up to 60db, the monitor will automatically dial back to your phone to remind you that there is poeple arround the monitor and they are talking , you can choose to listen or call back to monitor.