Buy from Amazon : br br Yongnuo YN-622N-TX LCD Wireless i-TTL Flash Controller For YN-622N i-TTL Wireless Flash Transceiver br br 1 It supports i-TTL and manual flash front-curtain sync rear- curtain sync and high-speed syncAuto FP the highest sync speed is 18000s br 2 It can remote change flash exposure compensation or flash output of each group supports different flash modes br 3 Supports the transmitter installed i-TTL flash in addition it supports the master unit on transmitter sets the parameters of each group br 4 This product is a wireless transceiver design the distance of remote control reaches 100M supporting 7 wireless channels and ABC three groups and with AF assist beam emitter function br 5 Yongnuo Authorized Seller with 2 YEAR Warranty 30 Days Return Refund Service