Features: The 4inch exhaust fan is make from ABS, It can bear to everyday wear and tear, guaranteeing long terms performances. Included remote control simplifies the operation of round exhaust fan from a distance. The check valves automatically opens during operation and closes when stopped. Low noise, easy to use. Easy to install: Reserve installation holes according to the opening size, install the ventilation fan in the reserved holes, and fix the screws to complete the installation. It can conveniently installed in locations such as garages, workshops, chicken coops, sheds, attics, greenhouses, offices, hospitals, and theaters, suitable for both indoor and outdoor, residential and commercial use. Specifications: Materials: Plastic Diameter: about 15cm/5.91inch Rear opening size: about 9.8cm/3.86inch Power: 15W Frequency: 50Hz Airflows: 100m³/h Voltages: 220V Package Includes: 1set Exhaust Fan note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to difference between different monitors, the picture may not reflect the actual color.