Rain x works great on the windshield, but I found it needs to be applied every month or so to be most effective, saltwater takes it off over time. It may still bead, but not great after a month, but it sure helps improve visibility a bunch, often enough to avoid using the wiper from casual spray. Running in the rain is also much better, the windows stay clearer. Not sure I would use it on eisenglass, that stuff needs special treatment and products, I'd be careful. There are products made for eisenglass that polish and clean the plastic and will make it bead just like the rain x will, yet they are formulated to not harm it. Eisenglass is not cheap, I'd use products made for it instead of taking a chance with anything else. My eisenglass gets mild soap and water when needed, otherwise rinses down and cleaned with the clear plastic cleaner after it dries that is made to clean it. It keeps the windows from figging up and keeps them clear and looking new.