A Countersunk Head Screw designates a screw with a head shaped in such a way that its top is either flush with or below the surface of the material into which it is being driven. This provides a smooth, even finish and makes it ideal for applications where aesthetics and functionality are equally important. https://www.dalloyedbolts.com/countersunk-flat-head-screw-manufacturers-suppliers-stockists-exporters.html