Metric Coarse Class 4.6 Hex Head Set Screws (Full Thread) are supplied with a spring washer & standard flat washer. The included washers are supplied at no extra cost. Supacheap Bolts Hex Head Class 4.6 Mild Steel Set Screws are manufactured to Australian Standard 1111 and our bright zinc plated finish offers corrosion protection and are suitable for general purpose internal and external bolting where maximum adjustment may be needed, and for fastening blind threaded components where a thread, running the full length is required. Typical applications for this very widely used product include steel fabricators, machine builders, automotive applications and the construction industry. Supacheap Bolts currently stock M4, M5, M6, M8 and M10 diameter set screws up to 40mm in length for certain diameters. Please note: Our Image is of a generic standard hexagon head set screw and set screw lengths are measured from under the head.