Designed by the American Board of Forensic Odontology (ABFO), this scale has become the standard for bitemark measurement and photography. The incorporation of three circles is useful in helping to the width of the legs, which are 1" (2.5 cm) wide. The 1 cm division lines are traced and extended across the photographic print to grid an image. Measurements within the image are then made relative to these inscribed 1 cm grid lines to compensate for any distortion resulting from non-parallelism between compensate for distortion resulting from oblique camera angles. Graduations are all metric except for the film and the object planes.