3a thread class right-hand 1.125" thread length double hexagon extended washer head style 18 thread quantity per inch zinc surface treated unrc thread series
2a thread class right-hand 1.250" thread length hexagon head style 0.092" hole diameter 20 thread quantity per inch cadmium surface treated unf thread series
3a thread class right-hand 1.481" thread length hexagon head style 12 thread quantity per inch navy special project passivate surface treated unjf thread series