Place bolts (or Type AA Hex Lock Bolts) have a special head design that provide a "locking" action between the head of the bolt and the material being clamped. The combination of the recess under the head of the slots in the top of the head cause the head to flex as it is tightened. This creates a spring action in the head that provides additional elastic elongation that is not provided by standard hex head cap screws. This spring action provides increased resistance to loosening in high vibration applications.
AFT's Place Bolts are manufactured from alloy steel and are through-hardened to Grade 8 strength as specified in the Society of Automotive Engineers standard SAE J429. The Place Bolts are made to the dimensional requirements of the General Motors (GM) standard to Type AA Hex Lock Bolts.