JEGS Stainless Steel Headers Studs add that finishing touch to your engine and eliminate rust that is common on steel or black oxide coated fasteners. Ideal for use with stainless steel or ceramic coated headers. Includes stainless studs, nuts and small diameter washers. Choose from hex nuts or 12-point nuts for extra wrench clearance that is needed with some headers. These studs are 3/8"(coarse thread, 3/8"-16 into the heads and fine thread, 3/8"-24 on the end for the nut).