Rain-ex is a nix on helmet screens as it removes the hardening layer of the optical plastics and causes them to be prone to scratches an swirls. This information from the plastics folks. I used the Plastic RainX on a few screens and found the problem to be true. Ran into a product they use on teh helicopter screens at work and fell in love with it 5 years ago, started carrying it on my site for that reason, great stuff 210 Polish, designed specifically for Lexan, and Polycarbonate plastics.
