tested with 2 YN 622c and a cannon 420EX flash and YN 568II. The manual is in English or Chinese. But the figures of ModOp seem clear. English is also understandable. Initiates high speed e-ttl.
The downside is the size of the box. Similarly fixing is not easy, there is little room to screw the knob.
Operation is relatively simple. I am happy with my purchase.