... steel,iron 2.free sample, more than 10 years supplier 3.ISO,SGS certification 4.size: M4-M33 din ... your requirement is okStandardGB,GB/T,DIN,JIS,BSW,ANSI,ISO & non-standard productsSurfacePlain, Yellow zinc, black phosphated, ... the best professional and experienced engineers( more than 8 years in this field) and strict QC and QA ... your need. din 933 stainless steel grade 10.9 hex bolt with metric thread