Our S-Series rods are our second tier off the shelf product. They are available in 4340 with ARP 2000. We purchase our steel (4340) in South America and comes with Industrial Certifications. As all products here in Saenz Performance, we use ARP bolts. This is an affordable rod with our quality standard on it! Saenz Performance Guarantees the quality of the steel, the forging, the heat treatment process and the dimensional sizes. There are no further guarantees either expressed or implied by Saenz Performance or any of their agents.