Features: 1.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...

Trouble shooting steps: -User need to do setting on Camera Flash light Control Menu to allow out-put flash light. -Long press button or examine if the battery in right position. YN560 IV=YN560III+YN560-TX, Supports Wireless Master...