... from zero to 22.5 degree. Features: 1. We could supply Ventilators made of different materials such as stainless steel, Galvalume ... . 2. Materials Assurance: The Base plate, Multi-angle neck, Turbine of the ventilator adopted 304 stainless steel, Aluminum-zinc Galvanized steel with ... insulating motivates system, so that the ventilators work more smoothly, supply a better effect of ventilation.