Grille shutters refer to a type of window covering that is made up of horizontal slats or bars, often made from metal or wood. These shutters are designed to allow light and air into a room while also providing privacy and security. They can be opened and closed by rotating the individual slats, much like blinds, but offer more visual control over incoming light due to their grid-like structure. Grille shutters are often used in commercial settings such as offices or restaurants, but they can also be a stylish addition to residential spaces.