INCRA scores again with its steel 18 Precision T-Rule. Select the proper slot or hole insert a .5mm mechanical pencil and mark the measurement with dead-on accuracy. Microfine 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 eyestrain! The metric versions include marking holes and slots at every 1mm 1/2mm and 1/4mm. INCRA Professional T-Rules even offer marking holes every 1/100 – a feature unmatched in the industry.