To maintain a reputation for "zero defects", ensure optimum quality control, and produce fasteners of exceptionally high quality, ARP controls all aspects of the manufacturing process, performing all operations in-house where they can be closely monitored. These thermostat housing bolts are a fine example of how ARP takes extraordinary steps to produce the very finest products of their kind on the market today. Nobody likes water leaks, and these are ARP's contribution to the solution. Manufactured from rust-proof stainless steel, these premium grade bolts are engineered to properly engage the manifold threads and resist loosening. The bolts feature conventional hex style heads, and washers are included.