... designs and standards provided by clients.Goal for quality control: Workshop qualified rate is 99%; the qualified rate of finished products ... steelcarbon steelspring steelGrade 10.9 steelChromate steelalloy steelGrade 12.9 steel,etc SizeM1 to M12, Special Custom MadeHeadHexagon Head, Cheese ... Slotted,PoziMaterial4.8,8.8,10.9,12.9,Steel, Stainless Steel A2,A4,18-8 and brass etcFinishZinc plated,Nickle ...