* 2.4ghz wirless long distance trnsmission system *transmit distande:3km (without block) *through 20ma/v cable to make the transmitter far away from signal source(such as vcd, dvd, vcr) *four channels could switch by manual *one channel output/input a/v signal * transmit power : 100 mw *power supply: dc9v 350ma * dimension: 580x85x50mm Package contents: two high gain antennas( one for transmitting and another for receiving) Two ac/dc adaptors One transmit box, one receiver box Two pieces of 18m connection cables