Steel is often used in applications where strength is the primary consideration
Zinc plating resists corrosion and has a reflective appearance
Flat head has a 90-degree cone-shaped bearing surface for use in countersunk holes and a flat top that fits flush with the mated surface
Pozi drive is similar to a Phillips drive but with straight sides and additional markings on the Phillips cross that reduce the likelihood of the Pozi drive driver slipping out and increase the amount of rotating force that can be used