Coupling Nut steel hex nut hex coupling nut/brass insert aluminium insert concrete brass insert/brass insert/ hex nuthex coupling nutbrass insert/brass nutbrass coupling nutbrass concrete insertspecifications:3/8",5/8",1/2",3/4",1",etc.Offer to sell various designs of coupling nuts,zinc plating or H.D.G.finish for your option. 1/2" Hex Coupling Nut