Countersunk Phillips machine screw, M5-0.80 x 12mm, in 304 stainless steel. The 90 degree head sits flush in a countersunk hole and the screw is fully threaded along its whole length. Needs a tapped hole or a nut - it will not cut its own thread in timber or unthreaded material. Also called flat head machine screws, CSK screws or countersunk metal thread screws.