... camera or DVR 4.Long distance:2k-3k 5.Low price Optical transmitter*4 channels available to avoid interference*Transmission distance:5000m ... demand in our factory ) , it could charge laptop , camcorder, mobile phone, iPOD, iPhone, PSP, PMP, MP3, MP4,DVR, portable DVD, pocket ... pleased to receive your inquiry.Hope to cooperate with you. Optical transmitter