Countersunk hex socket screw according to ANSI B18.3 standard with UNC inch thread, plain (uncoated) steel. Used in imported machinery, process equipment, and constructions built to UNC standards. The countersunk head provides a flush, low-profile installation suitable for mechanical and steel assemblies. The plain surface is ideal for dry environments or where post-coating is planned. Available in multiple sizes and lengths from SWEBOLT & BOTNIA BOLT.