Honda/Acura K24 - ProH625+ w/ARP Custom Age 625+ Fasteners. Made from aerospace grade, 4340 chromoly steel, BC high performance connecting rods deliver the reliability required to turn up the boost, the nitrous and/or the RPM range. Every rod is CNC machined, micropolished surface finish treatment, equipped with Aluminum/Silicone/Bronze pin bushings and finish honed to exacting tolerances.