A louver is a window blind or shutter with horizontal slats that are angled to admit light and air but to keep out rain and direct sunshine. The angle of the slats may be adjustable, usually in blinds and windows, or fixed.
Louvers are often made of aluminum, metal, wood, or glass. They may be opened and closed with a metal lever, pulleys, or through motorized operators.
Louvers are often used in windows or doors in order to allow air or light in while keeping sunshine or moisture out. They may be either movable or fixed.