... high quality iron,such as 1022,1018,1010,1008,1015...Medium carbon steel are 35k,45#,10B21,1035,CH38F,1039, ... less than 200mm .Threads/ Scrows Most scrows are available.such as :Self tapping threads "A","AB", Threads for chipboard screw,wood screw,drywall screw ... type,Torx type,trangle type,slotted point type,square type,Combined type...FinishZinc plated,Nickel plated,Dacroment Plated,chromium plated, ...