Weatherproof design: A tightly woven polyester shell with waterproof attributes and a sealed edge barrier blocks rain, moisture, and drafts around the window, helping keep the AC area dry and protected. Easy installation: Threestep setup with the included tension cord and tape kit allows fast, tool sealing. Just align, engage, and seal for a snug fit. Adaptable compatibility: Adjustable width fits a wide range of window openings and portable AC units, delivering consistent performance across different homes, apartments, and office spaces. Durable performance: Reinforced seams and density fabric resist deformation over time, maintaining an effective seal through frequent use and seasonal changes. Practical use scenarios: In a rental apartment with a portable AC, seal the window to reduce energy loss and prevent moisture intrusion. In rainy climates, install on bedroom or living room windows to keep the unit dry and improve cooling efficiency. In dorms or offices, deploy for quick, temporary window sealing during hot months to boost comfort and energy savings.