... 4GHz hopping frequency,120-200M remote range,OEM video doorbell,color video door phone,video intercom system,3.5" indoor unit,2.4GHz ... Spread Spectrum technology afford stable digital signal transfer;Auto photo record function when nobody answers the call;Built-in 16 ... ;Calling out,Surveillance,Automatically Unlock and Doorbell,etc functions;Camera Resolution:320*240 pixels;Power Supply: DC 12V,5A ...