Professional YN560-IV speedlite flash Supports Wireless Master Function Bundle With YN-560-TX For Canon & EACHSHOT Microfiber Cleaning Cloth YN-560-VI Supports Wireless Master Function The YN560 IV can be used as master unit, provides 3 independent groups with controlling ability, realizing remote control the flash mode, flash output and focal length of the YN560 IV and YN560 III.