Wafer head screws are distinguished by their low-profile, flat heads, which provide a sleek finish and minimize protrusion above the surface. The designation 1% 201% 4% refers to specific mechanical and material properties that make these screws particularly effective in certain applications. The combination of these percentages generally relates to the composition of the screw materials and their tensile strength.

The terms 3% and 4% often relate to the percentage of the anchor bolt’s yield strength in relation to the concrete’s compressive strength. For example, a 3% concrete anchor bolt means that the bolt can withstand loads up to 3% of the concrete's yield strength, while a 4% bolt can handle loads up to 4%. This distinction is vital for engineers and contractors, as it influences load calculations, safety factors, and the overall design of the structure.

Self-drilling screws are widely employed in multiple fields due to their versatility. In the construction industry, they are commonly used to attach metal roofing panels, siding, and steel frames. Their ability to create strong connections in metal components makes them invaluable for structural applications.