5mm-0.8 x 15mm Zinc Plated Steel Coarse Thread Coupling NutsType: Coupling Nuts
Driver Type: #8 Wrench
Thread Size: 0.8mm (Coarse)
Type: Coupling Nut
Specifications: DIN 6334
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.