Single channel radio-frequency transmitter and receiver set lets you trigger your studio flash setup in a studio or on location without PC cords, and without concern about cord length or other cameras setting off your lights. It has a range of up to 50 feet without the limitations of line-of-sight like infrared triggers, so the flash can be positioned freely. The compact transmitter mounts on a camera's hot shoe mount (or a flash bracket with the PC cord that is included). Receiver has an attached 3.5mm miniplug cord to connect directly to many monolights and includes an adapter for +" phono plug sync cord outlets. Very compact unit has low power consumption, so the user-replaceable #23A 12V battery installed in transmitter is good for 20,000 flashes. Receiver is powered by (2) AAA batteries, not included.