Star Drive flat head security machine screws are used for securing materials from being tampered with, such as license plates, grills in jails, schools, boats and cars. Used in food prep and processing areas. Also used in public bathrooms and other public spaces. You will often see security fasteners applied in metal to metal or metal to wood application. 18/8 or 18-8 Stainless steel prevent rusting and is corrosion resistant.