Grade 304 & Grade 316 UNC Hex Head Set Screws (Full Thread) are supplied with a corresponding grade spring washer & standard flat washer. The included washers are supplied at no extra cost. Supacheap Bolts Hexagon Head Grade 304 and Grade 316 Stainless Steel Set Screws are manufactured to ANSI Standard B18.2.1 / A2 304 and A4 316 and they offer higher levels of corrosion protection and are suitable for general purpose 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 stainless steel fabricators, machine builders, marine and automotive applications. Supacheap Bolts currently stock 1/4', 5/16", 3/8", 1/2", 5/8" and 3/4" diameter set screws up to 2.1/2" in length for certain diameters. Please note: Our Image is of a generic standard stainless steel hexagon head set screw and set screw lengths are measured from under the head.