The Pola-Screen was an early type of polarizing filter. Early examples were made under contract by Polaroid until their relationship with Kodak soured. Those examples are probably from the 1950s. It would be rotated to achieve the best polarizing effect, and being paired with cameras that were largely not SLRs, they needed some way to tell how to rotate the filter, hence the viewer. The user would look through the viewer notate the marked position, transfer this to the on camera filter, and then shoot.
Although most of the Kodak series filters are of good quality and usable today, the Pola-Screens were made by laminating a plastic sheet between two layers of glass. Over time, the plastic degrades and renders the filters unusable.