The Radio Slave 4i (Set) by Quantum is a versatile radio control system designed for photographers using three transmitters and receivers. This wireless radio trigger allows for convenient control of your flash heads, with each unit featuring a 6.3 mm (1/4) sync jack for seamless connectivity. The black color and compact design make it a sleek addition to any photography setup, offering flexible control and precision for capturing the perfect shot. Used to trigger flash strobes wirelessly from camera. Transmitter attaches to hot shoe and receiver is connected to strobe unit via sync cord. Sold as is.