A windshield wiper is a mechanical device used on vehicles to clear rain, snow, and debris from the windshield. It consists of a long arm that moves back and forth across the glass, using a rubber blade to wipe away moisture and improve visibility. Most modern vehicles have electric wipers that can be adjusted for different speeds. The operation of windshield wipers is typically controlled by a switch inside the vehicle, allowing the driver to activate them as needed. Some advanced systems include features like automatic rain sensing, which detects moisture on the windshield and activates the wipers without driver input.