NAS bolts Series 1303/6603, 160.000PSI resistance.
These fine-threaded, dimpled-head hex bolts have a minimum tensile strength of 160,000 psi and a minimum shear strength of 95,000 psi. Thread length is consistent within each diameter (1103/6203 series have a shorter thread), and grips are available in 1/16” increments beginning at 1/16”. Used in applications where a premium-quality, high strength bolt is necessary.