【Suitable for Most Blinds】The opening force is about 25kg/55lb, and the closing force is about 15kg/33lb. The automatic greenhouse ventilation kit is suitable for most blinds. 【Automatic Opening/Closing】The window opener automatically opens and closes as the temperature changes, it does not consume any power, energy-saving and environmentally friendly. 【Working Condition】It starts to open when the temperature reaches 17-25°C (63-78°F), and reaches the maximum opening when the temperature rises to 30-32°C (86-90°F). 【Excellent Quality】The automatic greenhouse vent is made of high-quality aluminum, which is not easy to rust and is durable. 【Easy To Install】Easy installation through the provided clips or screws, no battery or electricity is required, simple and convenient.