Used on f-15s acft. 2a thread class right-hand 0.402" thread length flat countersunk head style 56 thread quantity per inch passivate screw surface treated the oxide treatment must be black unc thread series
2a thread class right-hand 0.750" thread length watertight head style 20 thread quantity per inch packing under head to be silicone rubber per zz-r-765, cl 2 b, gr 70 unc thread series
2a thread class right-hand 0.102" thread length flat countersunk head style 40 thread quantity per inch passivate screw surface treated magnetic permeability shall not exceed 2.0 after fabrication unc thread series
2a thread class right-hand 0.589" thread length pan head style 56 thread quantity per inch passivate screw surface treated magnetic permeability shall not exceed 2.0 after fabrication unc thread series
3a thread class right-hand 4.492" thread length flat countersunk head style 24 thread quantity per inch cadmium or cadmium screw surface treated unjf thread series