GDLF Winter Cat Window Box – Cat Window Perch Catio with Windproof Cover & Door, Fits 24.3–38.8" Openings (Min Height 16")

Window Cat Perch Catio, Wood Cat Window Box, Window Catio for Indoor Cats. Suitable Single Hanging Window with an Inner Diameter of The Window Frame with A Net Opening Width of 24-35 in（White）

Grepatio Cat Catio 4 Tiers Outdoor Cat Enclosure Window Access, Indoor Cat House with Wheels and Removable Floor, Outside Large Cat Cage with Waterproof Roof, Kitty Cattio with Resting Box (Black)

Cat Window Box – Window Perches for Indoor Cats, Sturdy Cat Perch for Sunbathing, Napping & Nature Viewing, All Weather Use (Grey, 43.3")

KEIKI Catio Window Perch for Indoor Cats,Large Wooden Outdoor Cat Window Enclosure Box for Cats Sunbathing, Napping, Overlooking,Light Gray

5 DIY cat window box plans you can try at home

Window Catio Plans | MyOutdoorPlans

No-tool Cat Window Perch: Pine Wood Shelf for Your Cat to Gaze Outside - Etsy