... " Shank:smooth,grooved,spiral,twisted Diameter:1.0mm-6.0mm COUNTERSUNK HEAD CONCRETE NAILRaw materialC1045 , C1050 , C1055…Hardness45 – 55 degreeDiameter2.0mm—6 ... ,25kg/carton100pc/box,200pc/box,500pc/box and so on Countersunk head concrete nail