X-ray specs

X-Ray Specs consist of an over-sized pair of spectacles with plastic or cardboard frames and white cardboard "lenses" printed with concentric red circles, and emblazoned with the legend "X-RAY VISION".

The vanes of the feathers are so close together that light is diffracted, causing the user to receive two slightly offset images.

[3] X-Ray Specs were long advertised with the slogan "See the bones in your hand, see through clothes!"

These subjects may believe that the device does allow the wearer to compromise their modesty, so are liable to respond with a variety of amusing reactions.

Indeed, instructions with the packaging explain how to provoke such reactions, to "CONVINCE the gals that your X-Ray Spex are for real!"

"See through clothing" text on product package promises (falsely) the ability to engage in voyeurism
Approximation of the view through a pair of X-Ray Specs, showing the "bones" of the hand