The Sekonic RT-32CTL Radio Transmitter Module plugs into a compartment in the body of the Sekonic Flash Master L-358 meter, allowing it to trigger flash units from the meter for readings. With the RT-32CTL you can forget about sync wires or waiting for your assistant to trip the flash while you're in cordless mode. It's a great time-saver for solo photographers who can take an incident reading from the subject or a reflected reading from the camera position. The RT-32CTL has a 100' range & is compatible with Pocket Wizard radio triggering systems, as well as the Pocket Wizard Wireless Freedom partners (Photogenic, Norman, Lumedyne, Dyna-Lite & Profoto) with built-in Pocket Wizard radio technology.