Key benefits Reduces hot air infiltration and keeps cool air inside: the seal blocks the gap around the window, improving the performance of portable air conditioners and reducing energy loss. Durable non-woven fabric: material resists tearing and provides a long-lasting barrier without affecting window operation. Easy installation and removal: installs quickly on suitable windows and comes off cleanly without leaving adhesive residue. What it does Acts as a window gap seal that prevents warm outdoor air from entering and preserves conditioned air indoors. Ideal when using a mobile (portable) air conditioner in homes or offices. Compatibility and important notes (as specified) The window seal is only suitable for standard tilting windows or sashes. It is suitable for left and right opening windows, tilt windows and roof windows (not for sliding windows or doors). However, it cannot be used for left and right opening windows or doors. Primary applications Mobile air conditioner venting: use around the AC exhaust hose where it meets a tilt or casement window to limit heat gain. Bedrooms or home offices with tilt or roof windows: keeps rooms cooler and reduces run-time of portable AC units. Folding or casement windows: provides a temporary, residue-free seal when extra cooling efficiency is needed. Performance and features Material: durable non-woven fabric that balances flexibility and strength. Function: prevents hot air entry and helps retain cool air generated by portable air conditioners. Installation: designed for straightforward fitting and removal without damaging window frames or leaving sticky residue. Who should buy Anyone using a mobile air conditioner in a space with tilt-style, folding, casement, or roof windows who wants to improve cooling efficiency and reduce heat infiltration. Note: Please check your window type carefully against the compatibility statements above before purchase.