My own recent adventure at exploring the world of telescopes and eyepieces this helped me to make a new find.
Japanese Vixen the most reputable maker of 80s in their part of the world, this seems to be the source of headlight magnifier that many people still using at 2019.
First conclusion made this is that we have here a 50 years old product design.
Second conclusion could be that if you care for quality lens, then you might look harder to find such a headlight magnifier with the Made in Japan logo on it.