Have you fallen head over heel for your girl, but worry she doesn't return your affections? What you need is Nintendo's Love Tester! Crafted from the hands of the Game & Watch creator in 1969, it tests your luuuurve.
This Love Tester is the perfect gadget to sell to teenagers and foolish people. It requires a male and a female to hold the appropriate end of the Love Tester, and if the thing lights up, the two of you are in love.