INCRA T-Rules make it very easy to draw exact lines in either direction. INCRA scores again with its precision steel rule. Select the proper slot or hole, insert a .5mm mechanical pencil, and mark the measurement with dead-on accuracy.Micro-fine guide holes and slots at every 1/16″, 1/32″ and 1/64″ scale position instantly locate your sharp pencil or scribe at the exact measurement with zero uncertainty and no eye strain! Our Professional T-Rules even offer marking holes every 1/100″. This is unmatched in the industry.