Hex cap screws 9/16"-18 in zinc plated grade 5 steel. A hex cap screw is a cap screw with a hexagonal head, designed to be driven by a wrench. An ASME B18.2.1 compliant cap screw has somewhat tighter tolerances than a hex bolt for the head.
Diameter x Thread Pitch x Length from Under Head
FT = Full Thread
PT = Partial Thread