2a thread class right-hand 0.339" thread length flat countersunk head style 20 thread quantity per inch navy special project oxide surface treated unc thread series
3a thread class right-hand 0.425" thread length dished hexagon head style 0.990" grip length 28 thread quantity per inch aluminum surface treated unjf thread series
3a thread class right-hand 0.425" thread length dished hexagon head style 1.052" grip length 28 thread quantity per inch aluminum surface treated unjf thread series