I believe they aren't marketed directly in the US anymore (I suspect a patent dispute may be the reason). I looked at these before I decided to make my own turn signals and brake signal. The reviews of the first generation version complained that the wireless signal between the front and back units was blocked by the rider's body. I would expect that kink to have been worked out.

Even if the units had been available in the US, I ultimately wouldn't have purchased one. Price and the size of the turn signals (too small--each of my turn signals, front and rear have 22 super bright LEDs) coupled with user complaints about the batteries turned me off, although the concept is interesting.