●Super Slim Panel design. ●5-Blade design for high air volumn and low noise on operation. ●Buttrfly type back louver to avoid air and mosquito come indoors. ●The motor is made of silicon steel sheet and copper material for long service life. ●Built-in thermal cut-out protector for safer use. ●(HT Series) is working with additional timer function - the fan keeps working in 15min and off automatically when the trigger switch is off. ●(HH Series) is working with additional humidity function - When the air humidity is higher than 75%RH, the fan will be working automatically; when it is lower than 75%RH, the fan willbe off.