this screw has a threaded area that is 1/2 long and the thread is a 4-40 thread , nice original steel fastener from old mikitary stock , the button head measures 0.195 inch x 0.079 high the total fastener length is 0.557 long , these come loose as shown in the photos , great screws for your classic miltiary or antique project , dull silver plating , see photos for a view of the public owned specifications related to this screw . Also see our store we have more items like this and list new items each week , thank you rwk