1/2"-13 x 1-1/2" Zinc Inspection Hole Coupling Nuts (25 pcs.)

Diameter: 1/2"
Length: 1-1/2"
Material: Steel
Finish: Zinc
Driver Type: 11/16" Wrench
Thread Size: 13 (Coarse)
Style: Inspection Hole and Stop
Type: Coupling Nut

Box of 25.

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.