M6 Flat head: Zinc finish Flat Socket head cap screw M6x 1.0 pitch, uses M4 allen wrench to tighten/loosen. The nut size is M6, which uses a 10mm wrench/socket to adjust. These bolts typically used on steering wheels, floorpans, brackets etc
*To determine the length of a Flat head bolt, please measure the entire bolt including the head in millimeters