Stainless Steel Gravity Vent Louvre SMSis For air intake and exhaust. Made of stainless steel AISI304, polishing surface finish. With insect screen,fixing clips, rubber sealing. Can be used outside wall as well as inside. Made of stainless steel AISI 304, polishing surface finish. The shutter allows one-way air passage,resist water from entering the ducts. Quick and easy to install. Mechanical ventilation includes the pulsion or extraction of air by interference of fans. Examples of mechanical ventilation: kitchen hoods, bathroom and toilet exhaust fans, air supply or air extract systems, cloth drying machines, etc. Brushed stainless steel. Gravity shutter with lames. Prevents intake of cold air.