2a thread class right-hand 0.500" thread length 20 thread quantity per inch unthreaded portion of bolt is undercut to 0.193 min & 0.198 max unc thread series
2a thread class right-hand 0.625" thread length hexagon head style 20 thread quantity per inch material-astm, A354, grbd w ith zinc coating per astm-B633 unc thread series