I first ran across the original Rain-X product on a stormy Summer night at a '76 Truck Stop somewhere on the way to Endicott, New York back in 1975. I was working for IBM, and made the trip to and from Brooklyn, NY almost every weekend; driving I-80 to the Pennsylvania Turnpike. I pulled my Chevy Blazer under the gas pump canopy and out of the rain for 10 minutes in order to apply this stuff to my windshield, having been introduced to it by a seedy-looking trucker with a Southern drawl. "Slicker 'n snot on a glass doorknob!", he said..... and it sure was! I've been using the stuff ever since.
I apply Rain-X AF21212 Anti-Fog to the inside of my windshield (and other windows) to prevent fog and avoid using the windshield defogger (heat) It is essential if you've
bypassed the heater core. I use Rain-X Glass Treatment to treat the outside of the windshield, and add Rain-X RX11314 Windshield Washer Fluid Additive to Rain-X Windshield Washer Fluid.
In addition to almost completely negating the need for windshield wipers in the pouring rain and / or at highway speeds, Rain-X Glass Treatment makes scraping ice off the windshield in the winter a thing of the past; a sheet of ice on a windshield properly treated with this stuff will just push off with your hand. Splattered bugs and pigeon shit just wash off with the windshield washer. You can use it on your shower doors and tiles around the bathtub to make cleaning a breeze. The Anti-Fog stuff will keep your bathroom mirror from fogging.... and your sunglasses, too!