Yongnuo Radio Slave Hot Shoe Remote Wireless Flash Trigger-Transmitter and Two Receiver Set for NIKON D1/D2/D3/D50/D60/D90/D200/D300/D700 Digital SLR Cameras It can be used as wireless remote shutter release, but also can use it as a flash trigger Using global free 2.4GHz channel and FSK modulation system, and there's 15 frequency channels Flash sync speed is up to 1/250s and maximum operating distance is up to 100 meters with Half-Way Pressing and Full-way Pressing Support the flashgun wake-up function; you'll never miss any shot opportunity(Wake up can only used in TTL Compatible flash) Supports to control multiple flashguns and studio lights, multiple cameras to take shots at same time