Bottom Cuttable Bracket Design: The bottom of the waterproof window Ac unit cover is a cuttable design, which can be compatible with the window ac unit bracket. (Two threads of the bottom cover can be cut, which will not affect other lines and will not collapse.)Waterproof & Snowproof & Isolate Cold Air: The black window AC cover is treated with high-temperature press glue at each stitching joint to ensure waterproofing and windproofing. It not only protects the AC unit from sunlight and dust but also helps keep your room warm in winter.Double Straps Design: Outdoor winter window AC protection cover has two adjustable straps with a snap buckle, making the cover less prone to falling off due to wind, and easy to put on and take off.3 Layers Waterproof Material: Window air conditioner covers are made of 3 layers of material, the outside layer is high-quality 420D waterproof Oxford cloth, the middle layer is filled with antifreeze insulation pearl cotton, and the inner layer is antifreeze aluminum foil layer, It provides 100% protection for your AC unit during winter, keeping it safe from rain, snow, and wind.Please Choose the Right Size: The window AC unit cover has four sizes available, S: suit for most standard window ac units less than 3000 BTU. M: suit for most standard window ac units 3,000 - 7,000 BTU. L: suit for most standard window ac units 7,000 - 12,000 BTU. XL: suit for most standard window ac units of more than 12000 BTU. For detailed size information please reference the pictures.