Features: Portable Li-ion Battery System: Equipped with 2000mAh big-capacity li-ion battery, which makes the flash fire at least 600 times in full power possible. Adopts imported high quality lithium core, with advantages of long service life, high safety. Ultra-fast Charging Recycle System: Recycle time in full power is only 1.5s, you won't miss any splendid moment. Compatible for Canon 2.4G Wireless RT System: In wireless radio transmission flash shooting, one YN686EX-RT can be used as master unit to trigger YONGNUO RT speedlites and for Canon RT speedlites, and remotely control the flash mode and flash intensity of the slave unit. One YN686EX-RT can be used as slave unit to receive wireless signal from YONGNUO RT speedlites and Can0n RT speedlites, and realize remote TTL/M/MULT/Gr flash. Support Wireless Optical Master Function: In wireless optical shooting, YN686EX-RT can be used as master unit to trigger YONGNUO EX speedlites (except YN585EX)and for Cann EX series speedlites, and realize wireless flash in TTL/M/MULTI mode. Support Wireless Optical Slave Function: YN686EX-RT supports receiving wireless master signal from Canon speedlites, and it supports S1 and S2 flash mode. High Guide Number, High-speed Sync Function: GN60@ISO100, 200mm, supports TTL, M, MULTI and Gr flash, the max. sync shutter speed is up to 1/8000s. Support USB Firmware Upgrade: YN686EX-RT is equipped with USB port. Please visit YONGNUO official website to download the upgrade firmware and update the flash. Support Real-time Display of Battery Remaining Capacity: YN686EX-RT supports real-time display of battery remaining capacity, which is convenient for you to learn the status of charge. Support Lamp Head Electric Zoom Function: Support auto zooming and manual zooming, you can set flash coverage in the range of 20~200mm. Support Auto-save Setting, Custom Function (C.Fn) Equipped with Big Size LCD Display Screen.