With this remote trigger from Hähnel you control both your camera and an external flash. Place the receiver on the hot shoe of your camera and connect it to the trigger output. You can now await the right moment from a distance and take a picture with the remote control. Do you want to control an external flash? Then you turn the set around. You place the transmitter on the hot shoe of the camera. You place the receiver under your flash. When you take a picture now, the flash will fire automatically.