1. Yongnuo Yn600ex-rt Ii Hss 18000s Master Ttl Flash Speedlite For Canon 2. In Optical Transmission And Radio Transmission Flash Photography, Yn600ex-rt Ii Can Be Used As The Master Unit To Control Flash Mode, Exposure Compensation, Flash Ratio, Strobe Times And Strobe Frequency. 3. Wireless Transmission Flash Shooting, With Yn600ex-rt (ii), For Canon 600ex (ii-rt430exiii), A Yn600ex-rt Ii Can Be Used As A Set-top Box Master Or Remote Control Slave, A Total Of 15 Channels To Choose From, To Achieve Ttl , Manual Flash And Strobe. 4. In Optical Transmission Flash Shooting, Yn600ex-rt Ii Can Be Used As The Master To Trigger Yongnuo And For Canon Ex Series Flashes (except Yn585ex), Support 4 Channels, Realize Wireless Ttl, Manual Flash And Strobe. 5. One Yn600ex-rt Ii Can Receive Wireless Signals From The Host Yn600ex-rt Ii, Yn568ex Ii, 600ex(ii)-rt, 580ex Ii, Sb-910900800700, For Nikon Built-in Flash C Command And Canon 7d60d600d Camera Has Built-in Flash Wireless Signal To Realize Wireless Ttl, Manual Flash And Strobe. 6. Yn600ex-rt Ii, As A Professional Creative High Derivative Flash, Supports Ttl, M, Multi Flash. 7. Yn600ex-rt Ii Can Realize Ttl, Manual Flash, And The Maximum Shutter Synchronization Speed Can Reach 18000. 8. Ultra-fast Charging And Recycling System, Support External Power Supply 9. Yn600ex-rt Ii Is Equipped With Usb Interface, Supports Firmware Upgrade 10. Support Automanual Zoom: Support Auto And Manual Zoom, Flash Coverage Can Be Switched Between Auto, 20~200mm. 11. Supports Multiple Trigger Modes: Yn600ex-rt Ii Can Be Triggered By Camera Top Trigger, Pc Synchronous Trigger, Wireless Opticalradio Remote Trigger. 12. Auto Save Settings, Support Custom Settings (fn) 13. Equipped With Large-size Lcd Screen, Standard Pc Synchronization Interface 14. Specification: 15. Circuit Design: Insulated Gate Bipolar Transistor (igbt) 16. Guide Number: 60 (iso 100, 105mm) 17. Flash Mode: Ttl, M, Multi, Gr 18. Trigger Mode: Camera Setting, Wireless Master Mode, Wireless Slav