The front panel is larger and tighter. This feature provides a robust mounting design. It is silent and corrosion resistant. Long life of the motor against environmental factors. It has two-way operation. Meets the need for fresh air for indoor places; in the other direction, exudes dirty air in the interior. Electrical control structure does not require exter­nal control or panel. 
Used in offices such as offices, meeting rooms, schools, smoking rooms.