Actual sales locale:
http://rearview-helmets.com/
One YouTube review there ... and soliciting similar.
As to scoenye's reservations ... nope, don't expect any cognitive dissonance ay-tall; in fact, the juxtaposition of the fixed-mirror view + creative head motion can add a new dimension of knowing WTF You're At, especially in incipient dodgy situations (once, that is: you have indeed done some head-turning practice and taught brain how to choose instantly the er, 'stable platform-of-reference'.) And like that.
The sucker is  249 ... ulp. What's your bloody Liff worth?
(I'd already contemplated using one of the add-on car rear-tv thingies, but what a kluge to stick on a helmet and then find a place for the tiny screen.) I've always despised the left/right mirror dance, especially with certain helmet designs which limit peripheral field; then (unless on a Vincent) the mirrors are vibrating. Etc.
So if I keep the Kawasaki ... baby's new shoes will just have to wait. But even on a modrin scooter, preferably electric, I'd want this. Call me pre-Sold.
(Pity I didn't buy stock in this outfit; too late now)
I, omniscient. But humble.