SainSonic 2.4GHz DC12V Wireless 3W Audio Video AV Transmitter Sender Receiver CCTV It transmit AV signals by means of radio waves and can be used for wireless sharing of AV signals of DVD, DVR, CCD camera, IPTV, satellite STB, digital TV STB and other AV devices of several TV sets. 4 channels provided as options to ensure clear reception of video and audio. Effective range: Up to 100 meter line of sight, less than 80 meters if there are walls. With an external CCD camera, it can realize real-time field image monitoring in applications such as security system. It can also be used in AV transmission applications where the AV cabling is expensive.