In general,Oddleg calipers are used to scribe a line a set distance from the edge of workpiece. The bent leg is used to run along the workpiece edge while the scriber makes its mark at a predetermined distance, this ensures a line parallel to the edge.There is a caliper which has a slight shoulder in the bent leg allowing it to sit on the edge more securely, thelcaliper which lacks this feature but has a renewable scriber that can be adjusted for wear, as well as being replaced when excessively worn.