The AF540FGZ II has wireless master and slave TTL capabilities with access to 4 channels. It utilizes an optical pulse to transmit information and trigger flash units up to 13.1' away. Also, this unit can be set as a master, control, or slave unit and has access to a contrast control sync setting that enables the adjustment of the output of multiple flashes from a single unit.
An added feature for this flash is a constant LED light with 5 output settings for use during video, as an AF assist light, or as simply another light for your subject. Other settings include a multi-flash mode for stroboscopic photography as well as slow, high-speed, first and second curtain sync. Additionally, the AF540FGZ II runs on 4 AA batteries with a recycle time of 2.6-26.2 seconds and it comes with a case and stand.