Type A point has a conical tip and spaced threads that are suitable for forming threads in holes drilled in thin metals between 0.015" and 0.050" thick and resin impregnated plywood
Steel is often used in applications where strength is the primary consideration, and the zinc plating resists corrosion and has a reflective appearance
Hex washer head has six flat sides that a wrench can grip from the side in low-profile applications and has a flange for additional bearing surface to distribute the force over the material being fastened
Phillips drive has an x-shaped slot that accepts a Phillips driver and is designed to prevent over-tightening