Titanium Hex Head #10-32 x 5/8". Grip Length = 1/16" Thread Length = 9/16". The heads have been forged with 3/8" Hex Wrench, and the threads have been rolled for better fatigue resistance. Made from Titanium 6/4, ASTM B348 Grade 5 Min. UTS of 140Ksi. NAS6403