The Molnar H-Beam Connecting Rods are made from 4340 billet material, heat treated to increase tensile strength and are shot peened to increase fatigue life. All rods have a wear resistant bronze bushing for long wrist pin life and feature ARP fasteners. All Molnar Technologies connecting rods are finished here in the US at their factory. Tollerances are held to +/- .0001" which is the tightest tolerances you will find in the racing industry. These are a premium quality rod with features that aren't found anywhere else, including custom ARP 2000 bolts designed specifically by Molnar.