5/8"-11 x 1-7/8" Zinc Plated Steel Coarse Thread Inspection Hole Coupling NutsType: Coupling Nuts
Driver Type: 13/16" Wrench
Thread Size: 11 (Coarse)
Style: Inspection Hole and Stop
Type: Coupling Nut
Box of 20.
A coupling nut is a long nut tapped from each side to meet in the middle, rather than all the way through in the same direction, used to connect two threaded rods end to end.