Best Small Square Window Fan

Xpelair C4HTSR 4" Simply Silent Contour bathroom extractor fan with humidistat and timer, plus choice of square and round baffles, White, 240V

Xpelair C4HTS 4-inch Simply Silent Contour Extractor Fan Humidistat

CubeTech CTQF100t Smart LED 4" Inch Bathroom Extractor Fan with Timer Overrun Delay. Stainless Steel High Airflow Silent Bathroom Fan | Toilet Ventilation | Kitchen Ceiling Extractor | Fan Shower 240v

Xpelair DX100BTS Simply Silent Bathroom Extractor Fan with Timer, Adjustable Twin Speed, Ghost Air Movement Technology for Quiet Running, 100mm (4″), Square – Cool White

Caravan Roof Vent Fan, RV Air Vent Ventilation with Rain Sensor, Automatic Level Permanent Reversible Fan 12V for RV Motorhome (14" Remote control)

4" x 4" Inch / 100 x 100 mm White Air Vent Cover - Quality Steel Return Air Grilles - for Ceiling and Sidewall - HVAC - with Insect Protection Screen (3.93 x 3.93 inch, White)

Vent Systems 250 x 250 mm / 10'' x 10'' Inch White Soffit Vent Cover - Flat Square Air Vent Louver - Grille Cover - Built-in Insect Screen - HVAC Vents for Bathroom, Home Office, Kitchen

SEEKR Sirocco II, 7010CABBX, 3-Speed, 360 Degree Airflow, Direct Wire Gimbal Fan, 125/185 CFM, 12/24V, Black, 17.8cm Blade

Kair Smart 100mm Intelligent Extractor Fan with Humidistat Timer and Data Logger (Smart Fan Plus)

6'' x 6'' Inch / 150 x 150 mm Plastic Vent Cover - White - Square Soffit Vent - Exhaust Ventilation Louver - Air Inlet Grille Cover - Built-in Screen Mesh - HVAC Vent Duct Cover