7/16"-14 x 5/8" x 1-23/32" Zinc Plated Steel Coarse Thread Rod Coupling Nuts

Diameter: 7/16"
Diameter 2: 5/8"
Length: 1-23/32"
Material: Steel
Finish: Zinc
Driver Type: 5/8" Wrench
Thread Size: 14 (Coarse)
Style: Hex
Type: Coupling Nut

Box of 16.

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.