The lenses consist of two layers of cardboard with a small hole about 6 mm (.25 inch) in diameter punched through both layers. The user views objects through the holes. A feather is embedded between the layers of each lens.
X-Ray Specs were long advertised with the slogan "See the bones in your hand, see through clothes!" Some versions of the advertisement featured an illustration of a young man using the X-Ray Specs to examine the bones in his hand while a voluptuous (but fully-dressed) woman stood in the background, as though awaiting her turn to be "X-rayed."
