that is the length All hexagon head bolts in group 8 900 are G I I Grade 280 M steel 4 are cadmium or zinc plated except phosphate coated bo ts which are noted ... asterisk MATERIAL IDENTIFICATION GRADE u Q lz l S l l V GM 260 M GM 280 M GM 290 lM GM 300 M N0 TE The ident Hcation marks and corresponding GM material number