Circular duct fans series are combined with domestic and foreign advanced technology on design. The sizes of inlet duct and outlet duct are the same. Connected the fan and piping directly could save design and install cost on the piping. Special housing could reduce noise and vibration, best design on the impeller base on aerodynamic. Design for blow, exhaust, circle, renew and filtration could be used in hotel, marketplace, gymnasium, supermarket, store room and most of public place. 1)The sizes of inlet duct and outlet duct are 200mm; 2)Backward curved impellers, big flow, high efficiency, low noise. 3)Integrated into the external rotor motor so that the motor is equal to a wheel hub. So the motor can be cooled by the airflow efficiently to prolong life. 4)Connection box: Made of ABS contained material which can prevent burning.It is installed outward surface, connecting wire and disassembling is very convenient. 5)Model: JH100;JH125;JH150;JH160;JH200;JH250;JH315 Performance Parameter: 1) Static pressure: 0Pa 2) Speed: 2550rpm 3) Airflow: 780cbm/h 4) Power: 101W 5) Vol. / freq.: 240V / 50Hz 6) Current: 0.45A 7) Noise: 52dB