ARP 250-4203 Cylinder Head Studs Kit for 2008-2010 Ford Powerstroke Diesel 6.4L EnginesFastener Style: Stud Undercut Stud: No Head Style: 12 point Fastener Material: ARP2000 Fastener Finish: Black oxide Washers Included: Yes Cut to Fit: No Pro series cylinder head studs from ARP are cold forged to ensure molecular integrity. They are heat treated prior to thread rolling and machining and are rated at a whopping 220,000 psi. ARP Pro series kits are also available with 12 point nuts, and all kits come complete with hardened parallel