3a thread class right-hand 0.251" thread length flat countersunk head style 0.615" grip length 32 thread quantity per inch primer per mac process specification p.s.13421 cadmium surface treated unjf thread series
3a thread class right-hand 0.530" thread length flat countersunk head style 1.500" grip length 24 thread quantity per inch cadmium surface treated unf thread series
3a thread class right-hand 0.291" thread length flat countersunk undercut head style 28 thread quantity per inch cadmium screw surface treated bearing surface of head grooved to accommodate o-ring unjf thread series
2a thread class right-hand 0.120" thread length pan no. 2 head style 56 thread quantity per inch cadmium screw surface treated furnished with plastic sleeve over shank unc thread series