Wafer head screws are a countersunk head with a flat top surface and a cone-shaped bearing surface. The wafer's 70¡ã conical under head area does not extend to the outer edge of the head, providing a bearing surface of 16¡ã around the circumference of the under-head. Preferred head style for self-drilling screws. Provides the necessary bearing surface and flush fit in wood and softer materials. The head/shank fillet is contoured to strengthen the under head area.