I had to laugh at the Rearviz website, which says they have the "worlds first" wearable rear view mirror. I specifically remember those back in the 70s, a convex mirror with an elastic strap. I guess that company's not around anymore to claim differently.
(After the AMC car company (remember the Eagle?) went out of business, Subaru started claiming they had the "world's first" all wheel drive station wagon. But the Eagle was 4WD, so maybe that's technically true.)