Specification: YN-600EX-RT II is exactlly the same function as the Canon's best flash 600EX-RT, same functions, same power, even with same apprearance, TTL, HSS, Master Features Information: 1. Supports RT System One YN600EX-RT II can be used as on-camera master unit and remote slave unit of Canon's RT system, and supports Gr grouping mode. 2. Fully Compatible with YN-E3-RT, Canon's 600EX-RT / ST-E3-RT Wireless Signal 3. High Guide Number, Supports High-speed Sync GN60@ISO100, 200mm; supports high-speed sync TTL, manual flash, Gr grouping flash; the highest synchronous speed can reach 1/8000s. 4. Supports USB Firmware Upgrade The YN600EX-RT II equipped with the USB interface, supports firmware upgrade, the users can download the upgrade firmware through the Yongnuo official website to upgrade the flash. 5. Supports Wireless Optical Slave function The YN600EX-RT II supports YONGNUO, Canon's and Nikon's wireless optical master signal, supports S1 and S2 pre flash cancel mode. 6. Support Auto/Manual Zooming The YN600EX-RT supports auto and manual zooming, the zoom coverage is from 20~200mm. 7. Settings Save Automatically, Supports Custom Settings(Fn) 8. Ultrafast Charging Recycle System, Supports External Power Supply. 9. Equipped with Big Size LCD Display Screen, Standard PC Synchronous Interface. Compaible with : 1) Hot shoe TTL mode: 1Dx, 1Ds III, 1D III, 5DIII, 5DII, 6D, 7D, 70D, 60D, 50D, 40D, 700D/T5i, 650D/T4i, 600D/T3i, 550D/T2i, 500D/T1i, 450D/Xsi, 1100D, 1000D 2) Wirelss TTL Slave mode: for Canon Commander ST-E3-RT YONGNUO Commander YN-E3-RT Package Inlcuding: 1 X Flash Speedlite YN600EX-RT II 1 X Protector bag 1 X Mini stand 1 X Manual in English & Chinese