duplex 2 way radio Full-duplex, clear sound CE ... light twinkle, then is on Configure Code status. 2. Make the other machine on Configure Code status ... light becme red then go to synchronous mode. 2. Make the other machine go to synchronous ... , pass safety Certification. Details 1) Wireless frequency 2.4GHz 2) Full-duplex hands-free voice call, voice loud ... 43*35 Shell Material:Plastic duplex 2 way radio