... or DVR 4.Long distance:2k-3k 5.Low price video transmitter receiver*4 channels available to avoid interference*Transmission distance:2000m- ... and Humidity requirements: The normal condition should be: Temperature -10°C-50°C, humidity≤85%, Air pressure should between 85Kpa ... voltage can be set as customer’s demand in our factory ) , it could charge laptop , camcorder, mobile phone, iPOD, iPhone, ...