About this item PREMIUM MATERIAL: Made of high quality aluminium material, not easy to rust and durable in use. EXCELLENT DESIGN: Spring and support bar provide additional protection against wind damage. INSTRUCTIONS: The window opener automatically opens and closes as the temperature changes. EASY TO INSTALL: Universal, easy to install and use, suitable for any blind window, easy to use. ADVANTAGE: Easy fitting by clamps or screws provided, no batteries or electricity required.