This is the Godox AD600Pro TTL Flash with Lithium Ion Battery. It is a professional flash unit that is compatible with most TTL systems. It has built-in 2.4 GHz wireless X system and 600Ws, 1/256 to 1/1 power output with 1/220 to 1/10,100 sec flash duration, and up to 360 full-power flashes. The Godox AD600Pro is a TTL wireless flash with a lithium ion battery that has a maximum power output of 600Ws, 1/256 to 1/1 Power Output.