Detailed Product Description 1. Raw materials : AISI-C10222. Materials properties: surface carburization 0.10mm 3. Surface treatment; electric zine , phosphating.4. Examination : passed the salt-fog test more than 48 hours.5. Product spec : M3.5X25, M3.5X30,M3.5X35,M3.5X40,M3.5X45,M3.5X50 etc .. M3.9X11 , M3.9X32 etc .P.S. : we can make any size by order .