Yongnuo YN685EX-RF is a professional flash with high power and efficient power supply. This model is designed for Sony cameras (Multi Interface hot shoe). The device is equipped with a receiver and a transmitter enabling communication with the Yongnuo radio triggering system. It can operate both as a “slave” and “master” unit. The flash can operate in manual, strobe and TTL modes. It also offers HSS high-speed sync (up to 1/8000 s) and optical flash triggering (Sc, S1, S2). It also allows control of 5 groups of flashes within 16 channels. Powered by 4 AA batteries, it will take between 100 and 1500 shots depending on the power level selected.