I haven't tested them yet but a friend sent me this.....
tested the Pixel King thingy today.
got 2 extra receivers (1 tx + 1rx = 1 set). .. of the 3, 1 was faulty - couldn't sync at all, or worse: insisted on sending flash at minimum power.
the other two allowed sync at 1/8000, with on camera control (the +/- flash EV).. [