Powerful and almost as complete as my Nikon SB-910 for the third of the price. Fully controllable and adjustable from my camera via infrared transmission. Also tested radio controlled HSS dry 1/8000. Very good consistency in TTL. I have two that I use with the SB-910 and two YN 560 (manual flash) all in mostly remote controlled from a YN622N TX transmitter and 4 transceveurs YN622N. No problem even in difficult situations such as during wedding shopping.