The ad pic shows a woman wearing one, too, so unless she's a lesbian, she's trying to see a dick. And a guy who's dick is that small doesn't need a light, he needs a magnifying glass.
The day I can't handle a penis in total darkness is the day I retire from the gay scene altogether. Now it's true I enjoy seeing my handiwork, and a bit of illumination brings added pleasure to me. But a cock worth sucking needs no spotlights to service. Let's leave this product to the hets and move on.