5/16″ UNF x 2-1/2″ Hex

A 1/4 BSF hexagon set bolt (part threaded) Under head dimension: 1". Thread length: 1/2". Standard hexagon size (.445" A/F)Head machined flat (no markings).

A 1/4 BSF hexagon set bolt (threaded up to head)Under head dimension: 3/4". Standard hexagon size (.445" A/F)Head machined flat (no markings).

A 3/8 BSF hexagon bolt (part threaded)Under head dimension: 1-1/2".Thread length: 3/4" Standard hexagon size (.600" A/F)Head machined flat (no markings).

A 5/16 BSF hexagon bolt (part threaded)Under head dimension: 3-3/4".Thread length: 5/8" Standard hexagon size (.525" A/F)Head machined flat (no markings).