Reduced Wrench Hex Flange Bolts eliminate the need for a separate washer, distributing tightening force over a greater area. Common in automotive frame applications, flange bolts come in a wide range of thread diameters and finishes.
Coarse and Fine Thread Diameter sizes are specified / written differently. Coarse thread bolt sizes are commonly noted without the pitch.
Example: M12X1.75 is a coarse thread pitch, commonly identified as M12. M12X1.5 is a fine thread pitch, identified as M12X1.5 Fine.