Specifications: beisuda encoronmental friendly evaporative ventilators modern, high-tech products developed by scientists in australia, the usa, sweden and other countries, after years of research and testing. beisuda adopts direct evaporative technique, privides ventilation through an environmental friendly evaporative operating sustem. The beisuda encironmentally friendly ventilator fulfils the dual function of lowering the temperature while prociding a constant supply of fresh air, creating a fresh and comfortable environment.