The TT685C provide Godox 2.4GHz X System Radio Master and Slave modes.

The Radio Master mode can fire and control the complete Godox 2.4GHz Flash System, including cross compatibility with Godox 2.4GHz slave strobes for Canon, Nikon, Sony, M4/3, and Fuji.

An auto sensing Radio Slave mode can also be fired and controlled by Godox 2.4GHz Master flashes and Transmitters for Canon, Nikon, Sony, M4/3, and Fuji.

All with TTL and HSS available across platforms where applicable.

NOTE – Godox flashes purchased before July 2017 may also require a user installed firmware update to add the Olympus / Panasonic, and Fuji, radio slave modes (at least for TTL use).