Calumet Pro Series 2.4 GHz 4-channel Wireless Transceiver This unique, multi-functional, 4-channel tranceiver can be used either as a transmitter or as a receiver in tandem with other units to fire portable flash units, studio strobes or cameras. Used in combination with other Pro Series Wireless Transceivers, this system provides a wide range of convenient lighting & camera setups: When used with one unit attached to your camera as a transmitter, each unit used as a receiver can trigger up to two flashes as one time. Two units can provide wireless remote operation of your camera (for this you will require a dedicated shutter release cable to match your specific camera model. These shutter release cables are sold separately. A choice of 4 channels offers offers a range of synchronising options with multiple flash & camera setups, & prevents your flash from being triggered by other flash units around you, making it perfect for photographing events & other location assignments. There is no end to the creative possibilities with this multi-purpose, multi-functional system. Each transmitter has a male hot shoe for mounting to your camera, a female hot shoe to mount a portable flash & a 1/4" tripod lug. It also offers a PC sync for studio strobes. This system provides wireless triggering up to 350 metres. Calumet offers a wide range of cables for compatibility with most of todays popular cameras & flashes.