1/2 UNC NUT HT ZP GR 5
1/2" diameter & larger Grade 5 nuts are becoming obsolete, in future these will only be available in Grade 8.
Thread = 13 TPI (Thread per Inch)
UNC (Unified National Coarse Thread)
Hexagon head Across the Flats ( AF ) = 3/4"
Medium High Tensile Grade 5
Zincplated Finish