See it for $12.79 at Amazon - G/O Media may get a commission The inside of this innovative ventilation cap ... the wall. Cleaning this vent cover is just as easy. In conclusion, the 4in Exhaust ...

【Anti-corrosion Material】This roof vent cap is crafted from high-quality iron ... metal ducts and is compatible with kitchen and roof exhaust systems for efficient indoor air circulation.

They all have a cap over the exhaust opening ... it's easier to vent the fan through a side wall. In such cases, a wall-mount fan usually makes more sense than a ceiling-mount.