Light Distribution settings allow for Standard, Guide Number Priority, and Even Coverage settings. Radio master and slave functionality allows for the use of up to 15 flashes set up in 15 channels and 5 groups up to 98.4' away. Using optical transmission it can be set as a slave with an unlimited number of flashes within 4 channels and 3 groups. 10 custom Functions and 8 personal Functions are available for dialing in specific settings AF assist beam with range of up to 13.1'. LCD panel on rear for viewing and changing settings Fresh batteries will provide approximately 180 full-power flashes