ARP stainless steel header bolts are 15 percent stronger than Grade 8 steel. These 6-point bolts have a compact head that will allow a socket to fit into those tight, tricky spaces next to the headers. These bolts are both highly corrosion-resistant and heat-resistant. They have a polished finish. Washers are included. Size is M8 x 25UHL, which replaces any LS header/exhaust manifold bolt. Not only are they stronger but they look much better as well!