Grade: 4.8/6/8/8.8/10.9/12.9 etc Plain, black, zinc plated, hdg Material: carbon steel gennerall Manufacturer direct selling 10 years exporting experience Specification: Commodity name: Standard: din/astm/gb/iso/bsw, non-standard ( according to your drawing or sample), etc Material: carbon steel, stainless, alloy steel Grade: 4.8, 6.8, 8.8, 10.9, 12.9 etc Standard: din/astm/gb/iso/bsw, non-standard ( according to your drawing or sample), etc