Stain Guard. Water Repellant Coating GLÀZ Stain Guard™ is a nanotech coating that protects glass from all types of stains. It has high water repellant property that improves clarity and visibility by allowing water droplets to slide off during the rain. The non-stick formula also makes glass surfaces easy to clean, preventing watermarks. It is an all-weather protection that is guaranteed safe, easy to maintain, and gives clarity to all types of glasses and mirrors. GLÀZ® Stain Guard™ keeps your glass protected for up to six months. Protects glass from stains. Exhibits hydrophobic effect. Improves rain visibility and safety.