The Speedotron LED 4 Channel Radio Slave Set provides a coded radio signal that works indoors, outdoors, around corners and through walls. You can choose from 4 channels by matching the dip switches with the transmitter and receiver. The transmitter also has an LED readout for easy channel identification.
The system has a range of up to 150' (in unobstructed space). Line of sight is not required between the transmitter and receiver. The transmitter fits directly into a hot shoe, and also includes a PC sync socket. The receiver comes with a built-in 12" Mini Phone (3.5mm) sync cord, a Mini to 1/4" adapter, and also features a PC sync socket.