Yongnuo YN660 is the successor of the very popular YN-560 IV and the current Yongnuo manual speedlite flagship. Compared to YN-560 IV, YN660 now can control up to 6 groups in Radio Master Mode (up from 3), has a quick locking foot, increased zoom up to 200mm and improved GN of 66 meters (ISO 100, 200mm). It maintains compatible with current range of manual triggers YN560-TX, RF-605, RF-603 II, RF-603 and RF-602.