Resists Corrosion And Withstands Harsh Weather Conditions. Double Wheel Design: Provides Smooth And Effortless Window Movement. Pulley System: Reduces Friction, Making It Easy To Open And Close Windows. Smooth Operation: Enables Quiet And Smooth Window Movement. Long-Lasting Performance: Durable Stainless Steel Construction Ensures A Long Lifespan. Low Maintenance: Easy To Clean And Maintain.