Rain-X is known for its rain-repellent technology. How it works; Its unique hydrophobic properties change the surface tension of water droplets hitting the windscreen. By increasing the contact angle in a certain way, the "flat" drops regain their original round shape, with two immediate beneficial effects: The drops are more easily expelled from the driver's field of vision, improving safety and driving comfort. Keeps the windscreen clean by avoiding stubborn, sticky dirt such as mud, insects, etc.