Bathroom fan: This 120mm bathroom fan is made of ABS, an environmentally friendly material, lightweight, not easy to deform, with excellent heat resistance and durable.Operating voltage: 220V/50hz;Power: 16w;Energy savings!A lower power allows you to obtain a satisfactory air flow. Overheat Protection: Use an exhaust fan to ensure optimal cooling, a sealed motor using pure copper bearings generates less heat and extends the running time and life of the device.The built-in overheating protection device interrupts contacts when the motor overheats, acting as a power cutoff and double protection. Low noise: This 120mm wall fan is equipped with a brushless motor with double ball bearings, ensuring high efficiency, quiet operation and high quality performance.The improved motor reduces the friction coefficient compared to the normal motor, saving energy. Check valve: the rear of the 120mm exhaust fan is equipped with a double self-closing check valve to prevent outside air from entering the room and insects from flying inside..An excellent spring holds both doors in place, while the check valve can be removed at will. Wide range of applications: This 120mm bathroom fan is ideal for creating efficient HVAC systems in kitchens, bedrooms, offices, basements, warehouses, garages and other places where aConstant ventilation or a sewage system is required.