The original Sun Tex Shadecloth blocks up to 80% of the sun's damaging glare, while still admitting plenty of natural light and air movement. The ultimate in shading protection, this fabric blocks up to 90 percent of the sun's heat and glare before it reaches the window or glass. Made from heavy-duty coated polyester, they're mildew and fade resistant. Easy to install, easy to remove, they block the sun's glare through your windows, skylights, greenhouses, patios, and doors. These work best outside your windows. Stop the heat before it gets in your house!