1.Uses:Mainly used in concrete, cement and other construction projects 2.Material:#45 Steel/#55 Steel 3.Surface treatments:round head ,twisted shank,Diamond Point 4.Surface treatment：Galvanized,Polished,Phosphating black. 5.Length:1/2″-10″,BWG4-14 for all kinds of concrete nails. Phosphating black round head twisted shank concrete nail (3.4X40MM)are mainly for in concrete, cement and other construction projects .They have round head ,twisted shank,Diamond Point.#45-55 steel is used as raw material. This nail is Black phosphide.According to customer needs can also do polished, Galvanized and other surface treatment.It also supports custom packaging, such as boxes, plastic bags and cartons.Please contact us if necessary.