Auto-darkening filters are specialized lenses used in welding helmets that automatically adjust their tint in response to bright light. When a welder strikes an arc, the filter darkens to protect the eyes from harmful radiation and intense brightness. This feature allows for better visibility of the workpiece before and after welding. These filters typically use liquid crystal technology, which reacts quickly to changes in light intensity. This means welders can see clearly while setting up their work and then have instant protection when they begin welding. Auto-darkening filters enhance safety and comfort for professionals in the welding industry.