First of all: working with the Speedlite Transmitter is great fun. Anyone with Speedlites Canon something familiar, the lommt also with the transmitter from Canon cope easily as those of the display and buttons 600 Speedlites exactly. Changing the remote control flashes during the shootings should not be a problem. The group control of multiple flashes is quite easily possible, all of course with full ETTL functionality. The unit is fired with 2 AA batteries, which is very handy. At the limits of the reach of the unit I am so far met with no shooting; the radio receiver works instantly and without interference. Even the delivery is not objectionable with mtgelieferter pocket. Who wants to have it cheaper, z. B. the Yonguno 602 is well served. Otherwise meinerseirs applies: full purchase recommendation!