2 Pack YONGNUO YN560 IV YN-560IV Wireless Flash Speedlite Master / Slave Flash with Built-in Trigger System with 16 X EdisonBright Ni-MH rechargeable AA batteries bundle for Canon Nikon Pentax Olympus Fujifilm Panasonic Digital Cameras YONGNUO YN-560 IV Wrieless Speedlite Flash for Canon Nikon Camera / YN-560 III / RF-602 / RF-603 II / RF-605 / YN560-TX / YN-622C / YN-622N Wireless Transceiver Integrated - Fantastic with Three Controlling Groups - Yongnuo 2.4GHz Speedlite YN560 IV. YN-560 IV Flash Speedlite is a combination of YN-560 III and YN560-TX, it has built-in trigger system, so you can not only use it as flash speedlite, but also a flash controller Transmitter. Supports Wireless Master Function; Supports Wireless Slave Function, fully supports YN560-TXRF-603I/IIRF-602 Wireless transmitter; Multiple Trigger Synchronous Mode Supported 16 X EdisonBright Ni-MH rechargeable AA batteries included in bundle (Two of YN560IV bundle)