... M28 Or at your OptionsMaterial; Stainless Steel,Carbonic Steel, Copper,Aluminum or at your optionsThread; DIN,BSW,JIS,ANSI, ... 4. Hardness, Corrosion resistance We are Professional Manufacturer of all kinds of Fasteners (Nonstandard and Standard) such as Screws ... Head / etc ) , Rivets (Semi-tubular / Tubular / Blind/ etc.) , Nuts (Copper/ stainless steel etc.) , Thread Rod and Studs and Washers .We ...