Yongnuo YN600EXRT is a sibling of its far-more-expensive Canon counterpart. Yongnuo YN600EX-RT is the first flash speedlite from Yongnuo which supports Canon’s “game changing” RT Speedlite system. Canon’s RT flash system is one of the most advanced, yet easy to use flash systems available today. The unprecedented combination of a built in radio transceiver (with 2 way communication) along with TTL/HSS and Full Manual power control, on or off-camera, as well as support for external battery packs, and an intuitive menu system, makes it highly desirable for dynamic modern professional photographers.