This is for one upgraded rod bolt to replace the standard ARP 2000 alloy bolts shipped with all 3/8″ PRE Connecting Rods. For serious power builds, ARP’s 625 Plus super-alloy demonstrates superior fatigue cycle life, tensile strength, and complete resistance to corrosion and oxidation. ARP was the first manufacturer to develop and test the difficult manufacturing process for 625+ alloy for rod bolt use. The result is well worth the effort offering a new level of rod bolt reliability in extreme engine applications for less cost than lesser improved alloys. Push your performance VW or Audi engine with PRE Connecting Rods to the limits with ARP Custom Age 625+ alloy upgrade 3/8″ rod bolts!