1006606 is a Zinc Plated Finish button-head Socket Cap Screw manufactured by Bossard. It features a metric size of 4mm and a length of 8mm. The screw's thread is coarse, has a partial thread, and is cylindrical in shape and slightly rounded at the tip. It is zinc plated, and its head is shaped like a button, making it easy to install and remove. The head of the screw is designed to protrude enough for a tool to be able to grasp it, and the shoulder at the base of the head helps to ensure that the screw won't turn or slip when tightened. The screw is designed to be used in a variety of applications, such as in machines, engines, furniture, and electronic instruments.