Rain-X is a bottled polymer glass treatment that dramatically increases a car’s windshield visibility while driving through rain, snow, or sleet. It works by filling the tiny pores that are naturally present in any piece of glass. By doing so, the precipitation simply beads right off of the windshield instead of penetrating it fully. It’s really effective on cars, but it is also a good solution for preventing fingerprints on your iPhone, iPod touch, or iPad. After applying Rain-X, your screen will feel extremely smooth and will be much more resistant against fingerprints and smudges. It’s not a permant solution, so you’ll need to reapply it once every few weeks or so.