Interfit INT492 Hot Shoe Trigger Set Description. The 4-Channel Radio Transmitter Set is an affordable solution to triggering off-camera flash or strobes. Powered by two AAA batties this radio trigger system has a range of up to 30m 100. The 4-Channel Radio Transmitter Set is designed for use up to 1125 with a focal plane shutter or 1500 with a leaf shutter. Four channels allow you to isolate your lighting system when working alongside other photographers. This prevents your lights from being triggered inadvertently by other radio transmitters. The receiver is ideal for mounting hot shoe flashes onto light stands. Standard shoe mount flash units can be mounted directly onto the integral hot shoe which also provides the triggering power to the flash. Studio strobes may be fired from the PC Sync terminal on the side of the receiver.