Invisible grilles are commonly used in high-rise apartments, condominiums, and offices. The BOOST Invisible Grille from Korea is made up of 316 stainless steel, encased in PVC coating. This type of steel is not susceptible to rusting, hence, does not require maintenance. Unlike the traditional grills, the BOOST Invisible Grille are hardly noticeable from afar and blends seamlessly into any background. It does not interfere with your gorgeous view and provides extra protection for your family.