UNF Socket Head Countersunk Screws ASME B18. 3-2003 in A2 Stainless Steel
A countersunk headed screw conforming with ASME/ANSI B18.3, requiring a hex key (otherwise known as an Allen key) to fit. The countersunk head is typically used in conjunction with a countersunk hole providing a flush, snag free fit. Generally manufactured with a full thread, though occasionally some stock may include a partially threaded shank.