The wearing of eyeglasses with a gas mask always presents a problem. The Germans, however, have
devised a very simple and satisfactory solution. The lenses, conforming to the individual's particular
optical prescription, are set in approximately circular rims joined by the usual bridge. In place
of the usual hinged side members, there are double three-bar sliders through which are
fastened the two ends of a loop of tape, 0.3 inches wide. The tape fits over the ear and is
secured after adjustment by a hook at the end of each slider. Even though the tape may become
twisted, a gas-tight fit of the facepiece can be obtained. The glasses and extra tapes are
carried in a metal case.