These are custom hex flange screws we supplied to our automotive customer in grade 10.9.  The size and thread pitch is relatively common in the marketplace but the 10.9 class is a tricky find.  With the large volume required we had the parts domestically produced with black phosphate finish.  Measuring M12 X 1.75 X 30MM the hex flange head measured 23-25MM in flange diameter and 14.5-15.0MM across the flats.  Head height was set to 12MM +/-1MM, inclusive of the flange.  Full certs were available to the customer upon request.