Thanks for the pointer.
"The transmitter emits radio signal to the receiver when shutter is pressed. The receiver, once picks up the signal, will trigger off the external flash unit. Highest responding time is 1/1000s."
if........your camera can support 1/1000, i tried so many way for canon camera, maximum is 1/250 you still can get 1/320 with small gray line on the top.
only the old 1D support untill 1/500 (using CCD), else might try nikon camera, like D70 it can be triggered up to 1/500