YONGNUO YN600EX-RT YN600-EX-RT Flash Speedlite TTL 1/8000s for Canon Camera Compatible with Yongnuo YN-E3-RT Canon 600EX-RT/ST-E3-RT YONGNUO YN600EX-RT- Global First Aftermarket Radio Transmission Speedlite! One YN600EX-RT can be used as on-camera master unit and remote slave unit of Canon's RT system,and supports Gr grouping mode. GN60@ ISO100, 200mm; supports high-speed sync TTL, manual flash, Gr grouping flash, the highest synchronous speed can reach 1/8000s. The YN600EX-RT supports YONGNUO, Canon's and Nikon's wireless optical master signal, supports S1 and S2 pre flash cancel mode. The YN600EX-RT supports auto and manual zooming, the flash coverage can be changed between AUTO, 20~200mm